Is CVE-2026-34078 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-34078 being exploited in the wild.

How severe is CVE-2026-34078?

Critical severity, with a CVSS score of 10, published 7 April 2026.

Which products and versions are affected?

Flatpak < 1.16.4; Red Hat Enterprise Linux AppStream 8, 9, 10.

Is there a fix for CVE-2026-34078?

A patch was published on 2026-04-07: Fixed in version 1.16.4 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-34078 attacked?

It is attacked over the network, in an operating system.

Am I affected by CVE-2026-34078?

Check whether you run Flatpak or Red Hat Enterprise Linux AppStream at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-34078: Flatpak sandbox escape via symlink following in sandbox-expose

Q: Which products and versions are affected?

Flatpak < 1.16.4; Red Hat Enterprise Linux AppStream 8, 9, 10.

Q: Is there a fix for CVE-2026-34078?

A patch was published on 2026-04-07: Fixed in version 1.16.4 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-34078 attacked?

It is attacked over the network, in an operating system.

Q: Am I affected by CVE-2026-34078?

Check whether you run Flatpak or Red Hat Enterprise Linux AppStream at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-34078 · Severity: critical · CVSS 10 · Published 2026-04-07

Flatpak is a popular system used to run Linux applications in a secure, isolated environment (a sandbox). A critical vulnerability allows a malicious application to break out of this isolation by using specially crafted links to access any file on the host computer. This could allow an attacker to steal sensitive data or take full control of the user's system.

Technologies: Flatpak, Red Hat Enterprise Linux AppStream. Vendors: Flatpak, Red Hat.

Quick answers

Is CVE-2026-34078 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-34078 being exploited in the wild.
How severe is CVE-2026-34078?: Critical severity, with a CVSS score of 10, published 7 April 2026.
Which products and versions are affected?: Flatpak < 1.16.4; Red Hat Enterprise Linux AppStream 8, 9, 10.
Is there a fix for CVE-2026-34078?: A patch was published on 2026-04-07: Fixed in version 1.16.4 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-34078 attacked?: It is attacked over the network, in an operating system.
Am I affected by CVE-2026-34078?: Check whether you run Flatpak or Red Hat Enterprise Linux AppStream at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A symlink following vulnerability (CWE-61) exists in the Flatpak portal's 'sandbox-expose' options. The portal fails to properly validate paths, allowing a sandboxed application to provide symlinks that point to arbitrary locations on the host filesystem. When Flatpak resolves these links and mounts the resulting paths into the sandbox, the application gains full read/write access to host files. This primitive can be leveraged to achieve arbitrary code execution in the host context, representing a complete sandbox escape. The issue is resolved in Flatpak version 1.16.4.

Affected products

Flatpak Flatpak < 1.16.4
Red Hat Enterprise Linux AppStream 8, 9, 10

Timeline

2026-04-07: disclosed
2026-04-07: advisory: GitHub Advisory GHSA-cc2q-qc34-jprg published
2026-04-07: patched: Fixed in version 1.16.4

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.