CVE-2026-96276: flatpak Path Traversal

Vulnerability summary

CVE-2026-96276 is a medium (CVSS 6.5) Path Traversal vulnerability in flatpak. EPSS estimates a 0.37% chance of exploitation in the next 30 days, higher than 29.9% of scored vulnerabilities.

Timeline

1. 23-09-2026
   PublishedVulnerability first disclosed.
2. 27-09-2026
   Last modifiedVulnerability information updated.

Description

If a malicious SDK container declares an extension point with a crafted `directory` path, and a developer runs `flatpak build-init --writable-sdk --sdk-extension` with that SDK, attacker-chosen files could be written outside the working directory, since the target path is resolved via a function that allows `..` traversal.

• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.