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...

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.

CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity from

no source yet

Weakness

CWE-22

• www.cve.org/CVERecord?id=CVE-2026-96276
• nvd.nist.gov/vuln/detail/CVE-2026-96276
• access.redhat.com/security/cve/CVE-2026-96276
• bugzilla.redhat.com/show_bug.cgi?id=2539418
• github.com/flatpak/flatpak/security/advisories/GHSA-8qxj-x646-phcm