GHSA-35jh-r3h4-6jhm CVE-2021-23337

Command Injection in lodash

High RubyGemsnpm

Severity: 7.2 / 10; High · CVSS 3.1
Exploit chance (EPSS): 21.33%; Chance of exploitation in the next 30 days. Higher than 97.60% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-77 Improper Neutralization of Special Elements used in a Command ('Command Injection'); CWE-94 Improper Control of Generation of Code ('Code Injection')
Fix: Available; 3 packages have a fixed version

Description

lodash versions prior to 4.17.21 are vulnerable to Command Injection via the template function.

Affected versions

RubyGems

Package	Vulnerable	Fixed in
lodash-rails	`< 4.17.21`	`4.17.21`
lodash-rails	`< 4.17.21`	`4.17.21`

npm

Package	Vulnerable	Fixed in
lodash	`< 4.17.21`	`4.17.21`
lodash	`< 4.17.21`	`4.17.21`
lodash-es	`< 4.17.21`	`4.17.21`
lodash-es	`< 4.17.21`	`4.17.21`
lodash-template	`<= 1.0.0`	No fix yet
lodash-template	`<= 1.0.0`	No fix yet
lodash.template	`<= 4.5.0`	No fix yet
lodash.template	`<= 4.5.0`	No fix yet

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.

lodash-rails RubyGems → `4.17.21`

bundler

bundle update lodash-rails # Gemfile: gem "lodash-rails", ">= 4.17.21"

lodash npm → `4.17.21`

npm

npm install lodash@4.17.21

yarn

yarn add lodash@4.17.21

pnpm

pnpm add lodash@4.17.21

lodash-es npm → `4.17.21`

npm

npm install lodash-es@4.17.21

yarn

yarn add lodash-es@4.17.21

pnpm

pnpm add lodash-es@4.17.21

Severity breakdown

CVSS 3.1 7.2

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

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

Weakness

CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection')

The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

How to prevent it

Architecture and Design: If at all possible, use library calls rather than external processes to recreate the desired functionality.
Implementation: If possible, ensure that all external commands called from the program are statically created.
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.
Operation: Run time: Run time policy enforcement may be used in an allowlist fashion to prevent use of any non-sanctioned commands.
System Configuration: Assign permissions that prevent the user from accessing/opening privileged files.

CWE-94: Improper Control of Generation of Code ('Code Injection')

The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.

How to prevent it

Architecture and Design: Refactor your program so that you do not have to dynamically generate code.
Architecture and Design: 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 which code can be executed by your product. 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.
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. To reduce the likelihood of code injection, use stringent allowlists that limit which constructs are allowed. If you are dynamically constructing code that invokes a function, then verifying that the input is alphanumeric might be insufficient. An attacker might still be able to reference a dangerous function that you did not intend to allow, such as system(), exec(), or exit().
Testing: Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
Operation: Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).
Operation: Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).
Implementation: For Python programs, it is frequently encouraged to use the ast.literal_eval() function instead of eval, since it is intentionally designed to avoid executing code. However, an adversary could still cause excessive memory or stack consumption via deeply nested structures [REF-1372], so the python documentation discourages use of ast.literal_eval() on untrusted data [REF-1373].

References

Advisories

Fixes and patches

github.com/lodash/lodash/commit/3469357cff396a26c363f8c1b5a91dde28ba4b1c

Packages

github.com/lodash/lodash

Timeline

May 6, 2021 Published
Oct 17, 2026 Last updated by the source
Nov 1, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-r5fr-rjxr-66jc lodash vulnerable to Code Injection via `_.template` imports key names	Critical	Also affects lodash
GHSA-f23m-r3pf-42rh lodash vulnerable to Prototype Pollution via array path bypass in `_.unset` and `_.omit`	Medium	Also affects lodash
GHSA-xxjr-mmjv-4gpg Lodash has Prototype Pollution Vulnerability in `_.unset` and `_.omit` functions	Medium	Also affects lodash
GHSA-29mw-wpgm-hmr9 Regular Expression Denial of Service (ReDoS) in lodash	Medium	Also affects lodash
GHSA-p6mc-m468-83gw Prototype Pollution in lodash	High	Also affects lodash
GHSA-x5rq-j2xg-h7qm Regular Expression Denial of Service (ReDoS) in lodash	Medium	Also affects lodash
GHSA-jf85-cpcp-j695 Prototype Pollution in lodash	Critical	Also affects lodash
GHSA-4xc9-xhrj-v574 Prototype Pollution in lodash	High	Also affects lodash

Credits: G-Rath, ebickle, mitchell-codecov, nitaiapiiro

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