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Vulnerability · Published Apr 7, 2026 · Assigned by GitHub_M

CVE-2026-34078Flatpak has a complete sandbox escape leading to host file access and code execution in the host context

Critical 9.0

In plain English

A critical-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 1.7% (higher than 77% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)9.0Critical
Exploit odds (30 days)1.7%top 22.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Flatpak is a Linux application sandboxing and distribution framework. Prior to 1.16.4, the Flatpak portal accepts paths in the sandbox-expose options which can be app-controlled symlinks pointing at arbitrary paths. Flatpak run mounts the resolved host path in the sandbox. This gives apps access to all host files and can be used as a primitive to gain code execution in the host context. This vulnerability is fixed in 1.16.4.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10flatpak1.16.0-9.el10_2.1ALSA-2026:21757
AlmaLinux:8flatpak1.12.9-4.el8_10ALSA-2026:21756
AlmaLinux:9flatpak1.12.9-4.el9_8.1ALSA-2026:21755
AlmaLinux:10flatpak-devel1.16.0-9.el10_2.1ALSA-2026:21757
AlmaLinux:8flatpak-devel1.12.9-4.el8_10ALSA-2026:21756
AlmaLinux:9flatpak-devel1.12.9-4.el9_8.1ALSA-2026:21755
AlmaLinux:10flatpak-libs1.16.0-9.el10_2.1ALSA-2026:21757
AlmaLinux:8flatpak-libs1.12.9-4.el8_10ALSA-2026:21756
AlmaLinux:9flatpak-libs1.12.9-4.el9_8.1ALSA-2026:21755
AlmaLinux:10flatpak-selinux1.16.0-9.el10_2.1ALSA-2026:21757
AlmaLinux:8flatpak-selinux1.12.9-4.el8_10ALSA-2026:21756
AlmaLinux:9flatpak-selinux1.12.9-4.el9_8.1ALSA-2026:21755
AlmaLinux:10flatpak-session-helper1.16.0-9.el10_2.1ALSA-2026:21757
AlmaLinux:8flatpak-session-helper1.12.9-4.el8_10ALSA-2026:21756
AlmaLinux:9flatpak-session-helper1.12.9-4.el9_8.1ALSA-2026:21755
Alpine:v3.23flatpak1.16.4-r0ALPINE-CVE-2026-34078
Alpine:v3.24flatpak1.16.4-r0ALPINE-CVE-2026-34078
Debian:12flatpak1.14.10-1~deb12u2DEBIAN-CVE-2026-34078
Debian:13flatpak1.16.6-1~deb13u1DEBIAN-CVE-2026-34078
Debian:14flatpak1.16.4-1DEBIAN-CVE-2026-34078
Rocky Linux:10flatpak0:1.16.0-9.el10_2.1RLSA-2026:21757
Rocky Linux:8flatpak0:1.12.9-4.el8_10RLSA-2026:21756
Rocky Linux:9flatpak0:1.12.9-4.el9_8.1RLSA-2026:21755
Ubuntu:25.10flatpakno fix listedUBUNTU-CVE-2026-34078

Affected products (as reported)

VendorProductVersions
flatpak flatpak < 1.16.4

Weakness: CWE-61, CWE-59 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

References