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CVE-2026-44896VulnerabilityPublished Updated

src/mistune/directives/image.py, the render_figure() function concatenates figclass · In 3.2.0 and earlier,

Affects mistuneSource GCVE Database

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Authoritative record:CVE-2026-44896· Medium 5.3

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

CVSS 4.0 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Ubuntu 26.10mistunepkg:deb/ubuntu/mistune?arch=source&distro=stonkingOther threatsAffected
  • =3.1.4-1
Fixed in–
Ubuntu 26.10mistune0pkg:deb/ubuntu/mistune0?arch=source&distro=stonkingOther threatsAffected
  • =0.8.4-6
Fixed in–
Ubuntu 26.04 LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=resoluteOther threatsAffected
  • =3.1.3-1
  • =3.1.4-1
Fixed in–
Ubuntu 25.10mistunepkg:deb/ubuntu/mistune?arch=source&distro=questingOther threatsAffected
  • =3.0.2-2
  • =3.1.3-1
Fixed in–
Ubuntu 25.10mistune0pkg:deb/ubuntu/mistune0?arch=source&distro=questingOther threatsAffected
  • =0.8.4-4
Fixed in–
Ubuntu 24.04 LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=nobleOther threatsAffected
  • =2.0.4-2
  • =3.0.2-1
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.

References

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