What is CVE-2026-115350?

CVE-2026-115350 is a medium-severity vulnerability in Lepture Mistune, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-10-22.

How severe is CVE-2026-115350?

Medium severity. CVSS v3 base score is 6.1 out of 10.

XSS in Lepture Mistune

CVE-2026-115350

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.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-10-22 · last modified 2026-10-22.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Lepture Mistune

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

github.com/lepture/mistune/security/advisories/GHSA-96vr-jm8v-g22j (vendor-advisory)
www.vulncheck.com/advisories/mistune-before-3.3.0-stored-xss-via-include-direct… (third-party-advisory)

Frequently asked questions

What is CVE-2026-115350?: CVE-2026-115350 is a medium-severity vulnerability in Lepture Mistune, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-10-22.
How severe is CVE-2026-115350?: Medium severity. CVSS v3 base score is 6.1 out of 10.