CVE-2024-58266 — shlex
LOWCVE-2024-58266 is a low-severity (CVSS 3.2) CWE-116 vulnerability in shlex. A fix is available for shlex — see the affected versions and patch details below.
Multiple issues involving quote API in shlex
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-58266.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
shlexReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
Issue 1: Failure to quote characters
Affected versions of this crate allowed the bytes { and \xa0 to appear unquoted and unescaped in command arguments.
If the output of quote or join is passed to a shell, then what should be a single command argument could be interpreted as multiple arguments.
This does not directly allow arbitrary command execution (you can't inject a command substitution or similar). But depending on the command you're running, being able to inject multiple arguments where only one is expected could lead to undesired consequences, potentially including arbitrary command execution.
The flaw was corrected in version 1.2.1 by escaping additional characters. Updating to 1.3.0 is recommended, but 1.2.1 offers a more minimal fix if desired.
Workaround: Check for the bytes { and \xa0 in quote/join input or output.
(Note: { is problematic because it is used for glob expansion. \xa0 is problematic because it's treated as a word separator in specific environments.)
Issue 2: Dangerous API w.r.t. nul bytes
Version 1.3.0 deprecates the quote and join APIs in favor of try_quote and try_join, which behave the same except that they have Result return type, returning Err if the input contains nul bytes.
Strings containing nul bytes generally cannot be used in Unix command arguments or environment variables, and most shells cannot handle nul bytes even internally. If you try to pass one anyway, then the results might be security-sensitive in uncommon scenarios. More details here.
Due to the low severity, the behavior of the original quote and join APIs has not changed; they continue to allow nuls.
Workaround: Manually check for nul bytes in quote/join input or output.
Issue 3: Lack of documentation for interactive shell risks
The quote family of functions does not and cannot escape control characters. With non-interactive shells this is perfectly safe, as control characters have no special effect. But if you writing directly to the standard input of an interactive shell (or through a pty), then control characters can cause misbehavior including arbitrary command injection.
This is essentially unfixable, and has not been patched. But as of version 1.3.0, documentation has been added.
Future versions of shlex may add API variants that avoid the issue at the cost of reduced portability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | shlex | all versions | 1.3.0cargo update -p shlex --precise 1.3.0 |
Affected Products
shlexcomexDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for shlex, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update shlex to 1.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-58266 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This CVE was rated as Low severity. It involves three distinct issues: (1) Failure to quote characters, which can cause a single argument to be interpreted as multiple arguments in a shell, but does not directly allow arbitrary command execution; (2) Handling of null bytes in strings, which cannot be used in Unix…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.Source: Red Hat security advisory for CVE-2024-58266 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2024-58266 in your dependencies?
Find it across crates.io, including transitive dependencies.