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GHSA-4gxm-v5v7-fqc4 CVE-2026-55699

pnpm: Reserved bin name deletes PNPM_HOME during global remove

Medium npm
Severity
6.5 / 10
Medium · CVSS 3.1
Exploit chance (EPSS)
0.45%
Chance of exploitation in the next 30 days. Higher than 39.13% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-73 External Control of File Name or Path
Fix
10.34.2
Upgrade pnpm to this version or later

Description

<details> <summary>Maintainer Action Plan</summary>

Maintainer Action Plan

This report is ready to review with the shared patch branch. Start with the PR and the expected fixed behavior, then use the detailed exploit narrative below only if you want to replay the original path.

  • Advisory: CAND-PNPM-085 / GHSA-4gxm-v5v7-fqc4
  • Advisory URL: https://github.com/pnpm/pnpm/security/advisories/GHSA-4gxm-v5v7-fqc4
  • Shared patch PR: https://github.com/pnpm/pnpm-ghsa-j2hc-m6cf-6jm8/pull/1
  • Shared patch branch: security/ghsa-batch-2026-06-09
  • Patch commit: a93449314f398cf4bdf2e28d033c02d37395ad22
  • Base commit: origin/main 55a4035abf1ae3fe7208ba1f5ef43c5eff58ccec
  • Maintainer priority: appendix
  • Component: pnpm global add/remove bin cleanup
  • Patch area: bin name/path segment validation
  • Affected packages: npm:pnpm
  • CWE IDs: CWE-22, CWE-73
  • Conservative CVSS: 6.5 / CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
  • Next action: review the shared patch branch for this component, set the final affected version range, merge and release the fix, then publish or close the advisory.

Expected Patched Behavior

Reserved, dot, and path-segment bin names are rejected or ignored; global remove leaves PNPM_HOME and the sentinel file intact.

Files And Tests To Review

  • bins/resolver/src/index.ts
  • bins/resolver/test/index.ts
  • global/commands/test/globalRemove.test.ts
  • pacquet/crates/cmd-shim/src/bin_resolver.rs
  • pacquet/crates/cmd-shim/src/bin_resolver/tests.rs
  • .changeset/strange-bin-segments.md

Focused Validation

Run these from a checkout of the shared patch branch. They are the useful maintainer commands with machine-local artifact paths removed.

  • Use the private PR checks plus the patched replay coverage matrix for this candidate.

The full patched replay for the shared branch passed with all 20 candidates marked fixed. This candidate's replay evidence is results/CAND-PNPM-085-patched-result.json.

<!-- maintainer-action:end -->

Title

Reserved manifest bin names can make global package operations delete outside the global bin directory

</details>

Description

Summary

Manifest bin object keys such as "", ".", and ".." passed pnpm's bin-name guard. When a malicious package was installed globally, later global remove, update, or add-replacement flows could re-derive those names from the installed manifest and pass path.join(globalBinDir, binName) to removeBin. For "." this targets the global bin directory; for ".." this targets its parent.

Details

The vulnerable dataflow was:

  • bins/resolver/src/index.ts converted manifest bin object keys to binName and only required URL-safe text or $. Empty, dot, dot-dot, and scoped forms such as @scope/.. were not rejected after scope stripping.
  • global/packages/src/scanGlobalPackages.ts scanned installed global package manifests and returned manifest-derived bin.name values.
  • global/commands/src/globalRemove.ts, global/commands/src/globalUpdate.ts, and global add replacement logic joined those names to globalBinDir.
  • bins/remover/src/removeBins.ts recursively removed the resulting path.

Install-time checks did not close the gap: bin target paths were package-root checked, conflict checks looked at the same escaped path but did not reject reserved segments, and bin-link warning paths could leave the package installed for later global operations.

PoC

Run:

The script first performs a safe prepatch simulation in a temporary directory:

prepatch_reserved_bin_name=..
prepatch_delete_target=/.../cand-pnpm-085.XXXXXX/home
prepatch_deleted_global_bin_parent=true

It then validates the patched implementation:

./node_modules/.bin/tsgo --build bins/resolver/tsconfig.json
./node_modules/.bin/tsgo --build global/commands/tsconfig.json
./node_modules/.bin/eslint bins/resolver/src/index.ts bins/resolver/test/index.ts global/commands/test/globalRemove.test.ts
cd bins/resolver
NODE_OPTIONS="--experimental-vm-modules --disable-warning=ExperimentalWarning --disable-warning=DEP0169" ../../node_modules/.bin/jest test/index.ts --runInBand
cd global/commands
NODE_OPTIONS="--experimental-vm-modules --disable-warning=ExperimentalWarning --disable-warning=DEP0169" ../../node_modules/.bin/jest test/globalRemove.test.ts -t "global remove ignores reserved manifest bin names" --runInBand
cargo fmt --manifest-path pacquet/crates/cmd-shim/Cargo.toml --check
cargo test --manifest-path pacquet/crates/cmd-shim/Cargo.toml bin_resolver --lib
git diff --check -- bins/resolver global/commands/test/globalRemove.test.ts pacquet/crates/cmd-shim .changeset/strange-bin-segments.md pnpm-lock.yaml

The patched resolver no longer emits reserved bin names, and the global-remove regression proves the deletion sink receives only path.join(globalBinDir, "good").

Impact

Direct confidentiality impact was not validated for this primitive; the sink is deletion/corruption, not a read or disclosure path.

Affected Products

Ecosystem: npm

Package name: pnpm

Affected versions: versions before the patch that accept reserved manifest bin names in TypeScript global package flows.

Patched versions: pending release containing the shared bin-name hardening.

Severity

Corrected vulnerable severity: High

Corrected vulnerable vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

Corrected vulnerable score: 8.1

Final post-patch score: 0.0, not vulnerable after patch.

The original scan score was 8.3 with C:H/I:H/A:L. Revalidation removes direct confidentiality impact and raises availability to high because the sink can recursively delete the global bin directory or its parent.

Weaknesses

CWE-22: Improper Limitation of a Pathname to a Restricted Directory

CWE-73: External Control of File Name or Path

Patch

  • bins/resolver/src/index.ts now rejects empty, dot, and dot-dot bin names after scope stripping.
  • bins/resolver/test/index.ts covers empty, dot, dot-dot, and scoped reserved bin keys.
  • global/commands/test/globalRemove.test.ts proves global remove filters reserved manifest bin names before deletion and only removes a safe good shim.
  • pacquet/crates/cmd-shim/src/bin_resolver.rs mirrors the same reserved-name rejection; empty names were already rejected.
  • pacquet/crates/cmd-shim/src/bin_resolver/tests.rs extends parity coverage.
  • .changeset/strange-bin-segments.md records patch releases for @pnpm/bins.resolver, pnpm, and pacquet.

Pacquet parity is appropriate at the shared bin resolver/linker boundary because pacquet dependency-management commands can resolve and link package bins, even though the TypeScript-only global remove/update/add replacement flow is the concrete destructive-delete sink.

Validation

Passed locally:

The script passed TypeScript builds, ESLint, bins/resolver Jest, global-remove sink Jest, pacquet fmt/tests, and git diff --check.

Affected versions

npm

PackageVulnerableFixed in
pnpm
< 10.34.2
10.34.2
pnpm
>= 11.0.0, < 11.5.3
11.5.3

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

pnpm npm → 10.34.2

npm
npm install pnpm@10.34.2
yarn
yarn add pnpm@10.34.2
pnpm
pnpm add pnpm@10.34.2

Severity breakdown

CVSS 3.1 6.5

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Weakness

CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

How to prevent it
  • Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would b
  • Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
  • Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked. Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59). This includes: realpath() in C getCanonicalPath() in Java GetFullPath() in ASP.NET realpath() or abs_path() in Perl realpath() in PHP
  • Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].
  • Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
  • Architecture and Design, Operation: Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
  • Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap [REF-185] provide this capability.
  • Architecture and Design, Operation: Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software. OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
  • Architecture and Design, Operation: Store library, include, and utility files outside of the web document root, if possible. Otherwise, store them in a separate directory and use the web server's access control capabilities to prevent attackers from directly requesting them. One common practice is to define a fixed constant in each calling program, then check for the existence of the constant in the library/include file; if the constant does not exist, then the file was directly requested, and it can exit immediately. This significantly reduces the chance of an attacker being able to bypass any protection mechanisms that are in the base program but not in the include files. It will also reduce the attack surface.
  • Implementation: Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success. If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files. Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not. In the context of path traversal, error messages which disclose path information can help attackers craft the appropriate attack strings to move through the file system hierarchy.
  • Operation, Implementation: When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.

CWE-73: External Control of File Name or Path

The product allows user input to control or influence paths or file names that are used in filesystem operations.

How to prevent it
  • Architecture and Design: When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, and reject all other inputs. For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap provide this capability.
  • Architecture and Design, Operation: Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict all access to files within a particular directory. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
  • Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
  • Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would b
  • Implementation: Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59).
  • Installation, Operation: Use OS-level permissions and run as a low-privileged user to limit the scope of any successful attack.
  • Operation, Implementation: If you are using PHP, configure your application so that it does not use register_globals. During implementation, develop your application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.
  • Testing: Use tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session. These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

References

Advisories

Packages

Other links

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy it's related
GHSA-vx52-2968-3vc6
pnpm: Environment secrets exfiltrated via env-placeholder expansion in proxy settings read from an untrusted pnpm-workspace.yaml
High Also affects pnpm
GHSA-2rx9-3g3h-c2jv
pnpm: pacquet trust-lockfile install can create dependency symlinks outside the project
High Also affects pnpm
GHSA-vq4v-j7r6-jq4m
pnpm: A tarball dependency's manifest `name` escapes node_modules → arbitrary file write/overwrite on install
High Also affects pnpm
GHSA-c59q-g84q-2gj5
pnpm: Virtual store linker path traversal via unvalidated depPath name in lockfileToDepGraph
High Also affects pnpm
GHSA-qrv3-253h-g69c
pnpm: Path traversal in configDependencies env lockfile allows symlink creation outside node_modules/.pnpm-config
High Also affects pnpm
GHSA-72r4-9c5j-mj57
pnpm: `patch-remove` could delete project-selected files outside the patches directory
High Also affects pnpm
GHSA-fr4h-3cph-29xv
pnpm: Hoisted install imports lockfile alias outside node_modules
High Also affects pnpm
GHSA-v23m-ccfg-pq9h
pnpm: `stage download` writes outside its destination directory via manifest name/version traversal
High Also affects pnpm
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