CVE-2026-126205

5.3 MEDIUM Fix listed Denial of service Library

What it is

Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. Prior to 2.25.3, the Loofah HTML5 sanitizer checks href and xlink:href on elements in SVG_ALLOW_LOCAL_HREF with a regular expression whose line anchor and newline-matching whitespace cause an all-whitespace value to be rescanned from every line start. An attacker can submit an SVG reference element with a long multiline-whitespace attribute and consume CPU quadratically during sanitization. CRuby 3.1 and earlier and JRuby are affected, while CRuby 3.2 and later uses linear-time regular-expression matching. The default safelist reaches the vulnerable check without a configuration change. This issue is fixed in version 2.25.3.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-11-10 20:07 UTC ReservedThe CVE id was reserved by its CNA
2026-11-12 21:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-11-12 22:09 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: not scored yet.
Severity: 5.3 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-11-12 21:17 UTC
Last modified: 2026-11-12 22:09 UTC
Weakness: CWE-400 · Uncontrolled resource consumption
Record status: Awaiting Analysis

Attack profile CVSS 3.1 · 5.3

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-126205.md and follow it. Check whether this project is affected by CVE-2026-126205. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record