CVE-2026-97029

Flatpak's process ID namespace separation does not prevent a sandboxed app's kill(0, signal) or killpg(0, signal) calls from reaching processes outside the sandbox that share the same process group. A malicious or compromised Flatpak app can use this to cause denial of service by terminating processes outside its sandbox, such as the desktop shell.

• https://access.redhat.com/security/cve/CVE-2026-97029
• https://bugzilla.redhat.com/show_bug.cgi?id=2542698
• https://github.com/flatpak/flatpak/security/advisories/GHSA-f3p8-vr7v-gxf2