🛡️ CVE-2026-44896 — mistune

🟡 CVSS 6.1 — Medium ✅ No Known Exploit CWE-79 NVD
6.1
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Mistune has XSS via unescaped figclass/figwidth in Figure directive

In src/mistune/directives/image.py, the render_figure() function concatenates figclass and figwidth options directly into HTML attributes without escaping (lines 152-168).

This allows attribute injection and XSS even when HTMLRenderer(escape=True) is used, because these values bypass the inline renderer.

Other attributes in the same file (src, alt, style) are properly escaped; figclass/figwidth were missed.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. Rated impact: confidentiality none, integrity none, availability none.

Weakness class

CVE-2026-44896 is classified as CWE-79: Cross-site Scripting (XSS). User-supplied data is written into a page without escaping, so attacker script runs in the browser of anyone who views it.

Affected software

CVE-2026-44896 is recorded against 2 packages.

  • mistune (fixed in 3.2.1)
  • unknown

Timeline and source

Published on 8 May 2026 and last revised on 24 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Web)
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Package)
github.com (Web)

CVE-2026-44896 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity MEDIUM
CVSS Score 6.1
CVSS Vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
CWE CWE-79
Public Exploit ✅ No
Source NVD
Published 2026-05-08
Updated 2026-08-12
Modified 2026-07-24
Fix URL N/A

Affected Packages

Software From version Fixed in
mistune — 3.2.1
unknown — —

Similar Threats

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