Vulnerability · Published Sep 23, 2026 · Assigned by mitre
CVE-2026-96808
High 7.4
In plain English
A high-severity security flaw in Flatpak from Flatpak. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
In Flatpak before 1.18.1, the revokefs writer, used by the flatpak-system-helper to receive repository data from unprivileged callers, validated file paths by rejecting literal .. components but did not prevent symlink traversal. A malicious local user in an active local session could obtain two revokefs sessions via the system helper, create a symlink in one session pointing into the other session's directory, and retain a file descriptor through that symlink. This allowed the attacker to modify files belonging to a different revokefs session after they had been validated and imported by the system helper. In particular, an attacker could use this to tamper with ostree commit objects in the system repository after they passed signature verification, enabling root-controlled file writes to attacker-chosen paths and local root privilege escalation.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | flatpak | 1.16.0-9.el10_2.4 | ALSA-2026:80498 |
| AlmaLinux:8 | flatpak | 1.12.9-7.el8_10 | ALSA-2026:80687 |
| AlmaLinux:9 | flatpak | 1.12.9-4.el9_8.4 | ALSA-2026:80497 |
| AlmaLinux:10 | flatpak-devel | 1.16.0-9.el10_2.4 | ALSA-2026:80498 |
| AlmaLinux:8 | flatpak-devel | 1.12.9-7.el8_10 | ALSA-2026:80687 |
| AlmaLinux:9 | flatpak-devel | 1.12.9-4.el9_8.4 | ALSA-2026:80497 |
| AlmaLinux:10 | flatpak-libs | 1.16.0-9.el10_2.4 | ALSA-2026:80498 |
| AlmaLinux:8 | flatpak-libs | 1.12.9-7.el8_10 | ALSA-2026:80687 |
| AlmaLinux:9 | flatpak-libs | 1.12.9-4.el9_8.4 | ALSA-2026:80497 |
| AlmaLinux:10 | flatpak-selinux | 1.16.0-9.el10_2.4 | ALSA-2026:80498 |
| AlmaLinux:8 | flatpak-selinux | 1.12.9-7.el8_10 | ALSA-2026:80687 |
| AlmaLinux:9 | flatpak-selinux | 1.12.9-4.el9_8.4 | ALSA-2026:80497 |
| AlmaLinux:10 | flatpak-session-helper | 1.16.0-9.el10_2.4 | ALSA-2026:80498 |
| AlmaLinux:8 | flatpak-session-helper | 1.12.9-7.el8_10 | ALSA-2026:80687 |
| AlmaLinux:9 | flatpak-session-helper | 1.12.9-4.el9_8.4 | ALSA-2026:80497 |
| Debian:12 | flatpak | no fix listed | DEBIAN-CVE-2026-96808 |
| Debian:13 | flatpak | 1.16.6-1~deb13u2 | DEBIAN-CVE-2026-96808 |
| Debian:14 | flatpak | 1.18.1-1 | DEBIAN-CVE-2026-96808 |
| Rocky Linux:10 | flatpak | 0:1.16.0-9.el10_2.4 | RLSA-2026:80498 |
| Rocky Linux:8 | flatpak | 0:1.12.9-7.el8_10 | RLSA-2026:80687 |
| Rocky Linux:9 | flatpak | 0:1.12.9-4.el9_8.4 | RLSA-2026:80497 |
| Ubuntu:26.04:LTS | flatpak | no fix listed | UBUNTU-CVE-2026-96808 |
Affected products (as reported)
Weakness: CWE-61 · Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H