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.
Published: 2026-10-23
Score: 5.1 Medium
EPSS: n/a
KEV: No
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History

Fri, 23 Oct 2026 14:45:00 +0000

Type Values Removed Values Added
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.
Title Isar: Unprivileged user ownership of trusted repository GPG public keys storage after bootstrap
Weaknesses CWE-1290
References
Metrics cvssV3_1

{'score': 5.1, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'}


Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-23T14:31:41.863Z

Reserved: 2026-06-16T16:16:32.628Z

Link: CVE-2026-55222

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-23T15:17:32.563

Modified: 2026-10-23T15:17:32.563

Link: CVE-2026-55222

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-1290

    Incorrect Decoding of Security Identifiers