src/mistune/directives/image.py, the render_figure() function concatenates figclass · In 3.2.0 and earlier,
Affects mistuneSource GCVE Database
Not known to be exploited · CVSS 5.3 Medium · fixed in 3.2.1 : update mistune when convenient.
Data as of 9 Nov 2026, 14:18 UTC
- Patch
- Available – fixed in 3.2.1
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 26 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10mistunepkg:deb/ubuntu/mistune?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10mistune0pkg:deb/ubuntu/mistune0?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10mistunepkg:deb/ubuntu/mistune?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10mistune0pkg:deb/ubuntu/mistune0?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade to Mistune version 3.2.1 or later, where the vulnerability in render_figure() has been patched. No other specific mitigations are indicated. Applying this official fix fully addresses the issue.
Description
Mistune versions 3.2.0 and earlier contain a vulnerability in the render_figure() function within src/mistune/directives/image.py. This function concatenates the figclass and figwidth options directly into HTML attributes without proper escaping, enabling attribute injection and cross-site scripting (XSS) attacks. This occurs even when HTMLRenderer(escape=True) is used because these values bypass the inline renderer. The issue is fixed in version 3.2.1.