Medium severity · published Oct 22, 2026
CVE-2026-115350
Mistune before 3.3.0 Stored XSS via Include Directive HTML Files
New
6.1
CVSS
0.2%
EPSS
No
On KEV
Description
Mistune before 3.3.0 contains a cross-site scripting vulnerability in the Include directive that emits included .html, .xhtml, or .htm file content as raw block_html tokens. Attackers who can plant an HTML file readable by the renderer can reference it via an include directive, combined with path traversal, to execute stored scripts when escape=False is set.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 8% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MI
mistune · lepture
before 3.3.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-115350
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-115350
github.com
https://github.com/lepture/mistune/security/advisories/GHSA-96vr-jm8v-g22j
www.vulncheck.com
https://www.vulncheck.com/advisories/mistune-before-3.3.0-stored-xss-via-include-directive-html-files
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