CVE-2026-96276

EUVD-2026-85343
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.
Path Traversal
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
9.8 CRITICAL
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Debian logo
Debian Releases
Debian Product
Codename
flatpak
bookworm
vulnerable
bookworm (security)
vulnerable
forky
1.18.2-1
fixed
sid
1.18.3-1
fixed
trixie
1.16.6-1~deb13u2
fixed
trixie (security)
1.16.6-1~deb13u2
fixed
Common Weakness Enumeration
References
https://access.redhat.com/security/cve/CVE-2026-96276
https://bugzilla.redhat.com/show_bug.cgi?id=2539418
https://github.com/flatpak/flatpak/security/advisories/GHSA-8qxj-x646-phcm