6.1

CVE-2026-115350: Mistune before 3.3.0 Stored XSS via Include Directive HTML Files

Deferred
AliasesDEBIAN-CVE-2026-115350UBUNTU-CVE-2026-115350
Published 22-10-2026Last modified 29-10-2026

Vulnerability summary

CVE-2026-115350 is a medium (CVSS 6.1) vulnerability in lepture mistune. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8.5% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.3, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.1/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.19%
0%100%
Low · Change unavailable
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 22-10-2026
    PublishedVulnerability first disclosed.
  2. 29-10-2026
    Last modifiedVulnerability information updated.

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 metrics

7 scores · 4 sources · 2 versions

EPSS trend

Probability

0.19%

Chance of exploitation in the next 30 days

Percentile

9%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

23-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Debian1 product
  • mistuneAll versions (No fix recorded)
Lepture1 product
Ubuntu1 product
  • mistuneAll versions (No fix recorded)

3 vendors · 3 products

References

5 links