Improper isolation or compartmentalization in Flatpak - CVE-2026-97029

Vulnerability identifier: #VU152565

CSH Severity: Low

CVSS v4: 4.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-97029

CWE-ID: CWE-653

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to improper isolation or compartmentalization in Flatpak process ID namespace separation when a sandboxed app signals its current process group. A remote user can call kill(0, signal) or killpg(0, signal) to cause a denial of service.

Flatpak
Debian Linux
Anolis OS
flatpak
flatpak-devel
flatpak-libs
flatpak-session-helper
flatpak-tests
flatpak-doc
flatpak-selinux
flatpak (Debian package)

Install security update from vendor's website.

Flatpak - update to 1.18.4
flatpak - update to 1.18.4-1
flatpak-devel - update to 1.18.4-1
flatpak-libs - update to 1.18.4-1
flatpak-session-helper - update to 1.18.4-1
flatpak-tests - update to 1.18.4-1
flatpak-doc - update to 1.18.4-1
flatpak-selinux - update to 1.18.4-1
flatpak (Debian package) - update to 1.16.6-1~deb13u3

• https://github.com/flatpak/flatpak/security/advisories/GHSA-f3p8-vr7v-gxf2
• https://github.com/flatpak/flatpak/commit/a3cf27b5d6f365777259bd26ffa0d369c5ed7874

• Multiple vulnerabilities in Flatpak
• Anolis OS update for flatpak
• Debian update for flatpak