ljharb shell-quote up to 1.8.4 Accumulator parse algorithmic complexity

Summaryinfo

A vulnerability was found in ljharb shell-quote up to 1.8.4 and classified as problematic. Impacted is the function parse of the component Accumulator Handler. Such manipulation leads to algorithmic complexity. This vulnerability is traded as CVE-2026-13311. The attack may be launched remotely. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in ljharb shell-quote up to 1.8.4. Affected by this issue is the function parse of the component Accumulator Handler. The manipulation with an unknown input leads to a algorithmic complexity vulnerability. Using CWE to declare the problem leads to CWE-407. An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. Impacted is availability. CVE summarizes:

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.

The weakness was shared by bibu123456 as GHSA-395f-4hp3-45gv. The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-13311 since 06/25/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-39180). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Vendor

• ljharb

Name

• shell-quote

Version

• 1.8.0
• 1.8.1
• 1.8.2
• 1.8.3
• 1.8.4

Website

• Product: https://github.com/ljharb/shell-quote/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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