CVE-2026-13311: shell-quote — Fix

Description

shell-quote prior to 1.8.5 finalizes parsed tokens in parse() using Array.prototype.concat as a reduce accumulator, which reallocates and copies the entire growing array on every iteration. As a result parse() runs in O(n^2) time relative to the number of input tokens. An attacker who can supply an attacker-controlled string to any code path that calls parse() (no shell metacharacters are required; plain space-separated words suffice) can block the single-threaded Node.js event loop for an extended period with a small input, resulting in a denial of service. There is no code execution or data disclosure; impact is to availability only. Fixed in 1.8.5.

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CVSS v3.1 Score

7.5

HIGH

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

EPSS — Exploit Prediction

0.0036

Probability of exploitation

0.29%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-407 CWE-407

Affected Products

Vendor	Product	Versions
shell-quote_project	shell-quote	< 1.9.0

References

Advisories & Patches

https://github.com/ljharb/shell-quote/security/advisories/GHSA-395f-4hp3-45gv https://github.com/ljharb/shell-quote/security/advisories/GHSA-395f-4hp3-45gv

Other References

https://www.npmjs.com/package/shell-quote

Frequently Asked Questions

What is CVE-2026-13311? +

shell-quote prior to 1.8.5 finalizes parsed tokens in parse() using Array.prototype.concat as a reduce accumulator, which reallocates and copies the entire growing array on every iteration. As a result parse() runs in O(n^2) time relative to the number of input tokens. An attacker who can supply an attacker-controlled string to any code path that calls parse() (no shell metacharacters are required; plain space-separated words suffice) can block the single-threaded Node.js event loop for an extended period with a small input, resulting in a denial of service. There is no code execution or data disclosure; impact is to availability only. Fixed in 1.8.5. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-13311? +

CVE-2026-13311 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0036, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-13311? +

CVE-2026-13311 affects products from shell-quote_project, specifically: shell-quote. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-13311? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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