Quick answers
- Is CVE-2026-86320 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-86320 being exploited in the wild.
- How severe is CVE-2026-86320?
- High severity, with a CVSS score of 7.8, published 17 September 2026.
- Which products and versions are affected?
- Flatpak flatpak-builder.
- Is there a fix for CVE-2026-86320?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-86320 attacked?
- It is attacked with local access.
- Am I affected by CVE-2026-86320?
- Check whether you run Flatpak-Builder. 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
The vulnerability is a code injection flaw (CWE-94) in flatpak-builder's patch source handling. When use-git-am is set to true, the tool applies patches using Git's apply-patch functionality but fails to disable Git hooks (specifically post-applypatch hooks) that may be embedded in a malicious source. An attacker can craft a malicious source repository containing a Git post-applypatch hook that executes during the build process. Attack requires the build process to process an attacker-controlled or untrusted source with use-git-am enabled; interactive builds require user interaction to initiate the build, while automated CI/CD systems processing untrusted manifests may be exploited without additional user interaction. Successful exploitation results in arbitrary code execution with the privileges of the flatpak-builder process, potentially allowing access to or modification of build artifacts and system data.
Affected products
- Flatpak flatpak-builder
Timeline
- 2026-09-17: disclosed