CVE-2026-92812: Decap CMS < 3.11.0 Path Traversal via Sibling Directory Prefix Matching

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-16 · updated 2026-10-28
Weakness: CWE-22

Description

Decap CMS before 3.11.0 contains a path traversal vulnerability in the local proxy containment guard that uses plain string prefix comparison without path separator validation. Attackers can access sibling directories whose names begin with the repository directory name to read, write, or delete files outside the intended repository root.

Affected products

decaporg decap-cms: before 3.11.0 — fixed in 3.11.0

How to fix

Upgrade to a fixed version: decaporg decap-cms 3.11.0. Check the vendor advisory for mitigations.

References

https://github.com/decaporg/decap-cms/releases?page=2#release-decap-cms@3.11.0
https://github.com/decaporg/decap-cms/security/advisories/GHSA-5rrq-v82w-qpfr
https://github.com/geo-chen/oss/blob/main/decap-cms.md
https://www.vulncheck.com/advisories/decap-cms-path-traversal-via-sibling-directory-prefix-matching

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