# CVE-2026-115353: Mistune before 3.3.0 Path Traversal via include Directive

Status: published. Published: 2026-10-22. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- lepture / mistune (mistune): ≥ 0; < 3.3.0 (affected, semver); 3.3.0 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 9.2 (critical); CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 8.6 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: 0.39% as of 2026-11-04; percentile 33.07%

- SSVC: exploitation poc; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-22

## Exploit evidence

- exploit: https://github.com/lepture/mistune/security/advisories/GHSA-9jjx-3hq3-hx4j (ADP: CISA-ADP)

## References

- https://github.com/lepture/mistune/security/advisories/GHSA-9jjx-3hq3-hx4j (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/mistune-before-3.3.0-path-traversal-via-include-directive (CNA: VulnCheck; third-party-advisory)

- https://github.com/lepture/mistune/security/advisories/GHSA-9jjx-3hq3-hx4j (ADP: CISA-ADP; exploit)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-115353; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-115353; retrieved 2026-11-04; source updated Not reported

Revision: 04c0a8f1dcc7eb3f55389471c71779116fd92bf815e33711413cc2834efd3fba

Canonical: https://y2.dev/cve/CVE-2026-115353

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.