Vulnerability · Published Oct 22, 2026 · Assigned by VulnCheck
CVE-2026-115353Mistune before 3.3.0 Path Traversal via include Directive
High 8.6
In plain English
A high-severity path traversal in mistune from lepture. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities).
Severity (CVSS 3.1)8.6High
Exploit odds (30 days)0.4%top 66.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
Mistune before 3.3.0 contains a path traversal vulnerability in the RST include directive that allows attackers to read arbitrary files by supplying relative or absolute paths. Attackers can submit markdown containing include directives referencing ../ sequences or absolute paths to embed sensitive files like credentials or environment data in rendered HTML.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | mistune | no fix listed | DEBIAN-CVE-2026-115353 |
| Debian:13 | mistune | no fix listed | DEBIAN-CVE-2026-115353 |
| Debian:14 | mistune | no fix listed | DEBIAN-CVE-2026-115353 |
| Ubuntu:22.04:LTS | mistune | no fix listed | UBUNTU-CVE-2026-115353 |
| Ubuntu:24.04:LTS | mistune | no fix listed | UBUNTU-CVE-2026-115353 |
| Ubuntu:26.04:LTS | mistune | no fix listed | UBUNTU-CVE-2026-115353 |
| Ubuntu:26.10 | mistune | no fix listed | UBUNTU-CVE-2026-115353 |
Affected products (as reported)
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
References
- GitHub Security Advisory (GHSA-9jjx-3hq3-hx4j) vendor-advisory
- VulnCheck Advisory: Mistune before 3.3.0 Path Traversal via include Directive third-party-advisory