CVE-2026-55222 Isar: Unprivileged user ownership of trusted repository GPG public keys storage after bootstrap
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-55222?
CVE-2026-55222 is a medium-severity vulnerability in ilbers isar, published on 23 Oct 2026.
Official description
Isar is an integration system for automated root filesystem generation. In versions 0.11 and newer, /etc/apt/trusted.gpg.d is created manually during bootstrap setup to be able to deploy local keys. By that, the directory is owned by the calling user (the one that executes Isar) instead of root. If the calling user's id is identical to one of an unprivileged user inside the image, this user is able to alter existing keys and deploy new ones, silently breaking the apt repo integrity protection. The issue is has no impact on those images that use an immutable rootfs, or if apt is never invoked. Changing only the keys does not trigger an exploit, it's just one step in a chain. An attacker would also have to manipulate a remote repo or intercept non-secure communication with it. This issue has been patched via commit 29e84ed.
Weakness: CWE-1290
Which versions are affected by CVE-2026-55222?
How do I fix CVE-2026-55222?
No fix has been published for CVE-2026-55222 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-55222 being exploited?
There is no known exploitation of CVE-2026-55222 in the wild and no public exploit code.
Sources
Also known as GHSA-rq66-pfw5-whqq.