Vulnerability · Published Sep 23, 2026 · Assigned by redhat
CVE-2026-96276Flatpak: flatpak: arbitrary write in host context via flatpak build-init
Medium 6.5
In plain English
A medium-severity path traversal in Red Hat Enterprise Linux 10 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | flatpak | no fix listed | DEBIAN-CVE-2026-96276 |
| Debian:13 | flatpak | 1.16.6-1~deb13u2 | DEBIAN-CVE-2026-96276 |
| Debian:14 | flatpak | 1.18.1-1 | DEBIAN-CVE-2026-96276 |
| Ubuntu:26.04:LTS | flatpak | no fix listed | UBUNTU-CVE-2026-96276 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | see references |
| Red Hat | Red Hat Enterprise Linux 7 | see references |
| Red Hat | Red Hat Enterprise Linux 8 | see references |
| Red Hat | Red Hat Enterprise Linux 9 | see references |
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
References
- https://access.redhat.com/security/cve/CVE-2026-96276 vdb-entry, x_refsource_REDHAT
- RHBZ#2539418 issue-tracking, x_refsource_REDHAT
- https://github.com/flatpak/flatpak/security/advisories/GHSA-8qxj-x646-phcm