GHSA-r5jh-q2mw-gcx4 CVE-2026-50568 GO-2026-6130

Fission: SanitizeFilePath lexical HasPrefix bypass permits sibling-directory escape

Low Go

Severity: 3.6 / 10; Low · CVSS 3.1
Exploit chance (EPSS): 0.11%; Chance of exploitation in the next 30 days. Higher than 1.53% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-41 Improper Resolution of Path Equivalence
Fix: 1.25.0; Upgrade github.com/fission/fission to this version or later

Description

SanitizeFilePath in pkg/utils/utils.go validated that a path stayed under a safe directory by calling strings.HasPrefix(path, safedir). This is a lexical check, not a directory boundary check: /packages-extra/evil starts with /packages, so it passed. The function did not enforce a path-separator boundary, so any sibling directory whose name began with the safe-directory string was accepted.

Callers included the builder's Clean handler (pkg/builder/builder.go:208) and the fetcher's Fetch / Upload handlers (pkg/fetcher/fetcher.go). A tenant who could pre-create or control a sibling directory under the fetcher / builder's shared volume could induce a write or read outside the intended safe directory.

Affected

Project: github.com/fission/fission
Versions: all versions through v1.24.0 with SanitizeFilePath in the tree
Audited commit: 647c141
Component: pkg/utils/utils.go:SanitizeFilePath
Callers: pkg/builder/builder.go:157,164,208, pkg/fetcher/fetcher.go:296,311,450,496,565,571
Configuration: default; requires a sibling directory to the safe dir to exist on the filesystem

Fix section (paste into the Fix / Patches field)

Fixed in v1.25.0 by:

PR #3445 (commit 8298e33e) — migrate every SanitizeFilePath call site (fetcher: storePath / tmpPath / secretDir / configDir / rename + writeSecretOrConfigMap; builder: srcPkg / deployPkg path validation and srcPkg stat) to new pkg/utils/root.go helpers (RootJoin, RootStat, RootWriteFile, RootMkdirAll, RootRename) that operate through os.Root. os.Root enforces directory confinement in the kernel and is recognized by CodeQL go/path-injection as a traversal barrier.
PR #3446 (commit 5aac6f0b) — delete the deprecated SanitizeFilePath itself once no callers remained. The vulnerable function no longer exists in the tree.

Affected versions

Go

Package	Vulnerable	Fixed in
github.com/fission/fission	`< 1.25.0`	`1.25.0`

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.

github.com/fission/fission Go → `1.25.0`

go

go get github.com/fission/fission@v1.25.0 && go mod tidy

Severity breakdown

CVSS 3.1 3.6

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

Attack vector: Local
Attack complexity: High
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Weakness

CWE-41: Improper Resolution of Path Equivalence

The product is vulnerable to file system contents disclosure through path equivalence. Path equivalence involves the use of special characters in file and directory names. The associated manipulations are intended to generate multiple names for the same object.

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.
Implementation: Use and specify an output encoding that can be handled by the downstream component that is reading the output. Common encodings include ISO-8859-1, UTF-7, and UTF-8. When an encoding is not specified, a downstream component may choose a different encoding, either by assuming a default encoding or automatically inferring which encoding is being used, which can be erroneous. When the encodings are inconsistent, the downstream component might treat some character or byte sequences as special, even if they are not special in the original encoding. Attackers might then be able to exploit this discrepancy and conduct injection attacks; they even might be able to bypass protection mechanisms that assume the original encoding is also being used by the downstream component.
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.

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2026-50568

Packages

github.com/fission/fission

Timeline

Jun 10, 2026 Published
Aug 18, 2026 Last updated by the source
Nov 1, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-7m8x-qg2j-4m3v Fission: MessageQueueTrigger scaler manager materializes Secret values into Deployment envvars and accepts arbitrary user PodSpec	High	Also affects github.com/fission/fission
GHSA-qf5v-m7p4-95rp Fission: Incomplete capability denylist in Environment/Function PodSpec validation allows tenant-added CAP_SYS_TIME and cross-tenant node wall-clock corruption	High	Also affects github.com/fission/fission
GHSA-vchh-r53j-8mpw Fission: HTTPTrigger admission omits RelativeURL / Prefix validation; kubectl apply bypasses CLI checks	Medium	Also affects github.com/fission/fission
GHSA-q6vm-xqc9-v3ff Fission: Zip Slip in pkg/utils/zip.go:Unarchive allows fetcher to write outside the destination directory	High	Also affects github.com/fission/fission
GHSA-m63v-2g9w-2w6v Fission: Environment Runtime.Container and Builder.Container SecurityContext bypass allows privileged pod creation	Critical	Also affects github.com/fission/fission
GHSA-8wcj-mfrc-jx5q Fission builder pods auto-mount the fission-builder ServiceAccount token in the user-supplied builder container	Medium	Also affects github.com/fission/fission
GHSA-gx55-f84r-v3r7 Fission Environment CRD podspec passthrough enables hostPID/hostNetwork/privileged pods, node escape	Critical	Also affects github.com/fission/fission
GHSA-v455-mv2v-5g92 Fission Container Executor Function PodSpec Injection Leading to Node Escape	Critical	Also affects github.com/fission/fission

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