GHSA-r7qv-8r2h-pg27 — shlex
LOWGHSA-r7qv-8r2h-pg27 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 GHSA-r7qv-8r2h-pg27.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-r7qv-8r2h-pg27 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,238 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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 |
Detection & 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 GHSA-r7qv-8r2h-pg27 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-r7qv-8r2h-pg27 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-r7qv-8r2h-pg27. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-r7qv-8r2h-pg27 in your dependencies?
O3 Security finds GHSA-r7qv-8r2h-pg27 across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.