CVE-2026-44897: lepture mistune · Cross-site Scripting
Affects lepture mistuneSource CVE Database V5
Not known to be exploited · CVSS 6.1 Medium : upgrade to 3.2.1 when convenient.
Data as of 29 Oct 2026, 19:04 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.2.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A: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 29 Oct 2026.
What to do
Upgrade lepture mistune to 3.2.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| lepturemistune | Affected
| Fixed in
|
PyPImistunepkg:pypi/mistuneOther 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 Mistune to version 3.2.1 or later, where this vulnerability is fixed by properly escaping the id attribute in HTMLRenderer.heading(). Since this is a library vulnerability, applying the official fix by updating the package is the recommended remediation. Patch status is confirmed fixed in version 3.2.1. No alternative mitigations are indicated.
Description
Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening <hN> tag by string-concatenating the id attribute value directly into the HTML — with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character " in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element. This vulnerability is fixed in 3.2.1.