Isar: Unprivileged user ownership of trusted repository GPG public keys storage after bootstrap

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-55222
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-23 15:17:32 UTC
Updated2026-10-23 21:17:24 UTC
DescriptionIsar 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.

Risk And Classification

Primary CVSS: v3.1 5.1 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Problem Types: CWE-1290 | CWE-1290 CWE-1290: Incorrect Decoding of Security Identifiers

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.1MEDIUMCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
3.1CNADECLARED5.1MEDIUMCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Ilbers Isar affected >= 0.11, <= 1.1 Not specified

References

ReferenceSourceLinkTags
github.com/ilbers/isar/security/advisories/GHSA-rq66-pfw5-whqq [email protected] github.com
github.com/ilbers/isar/commit/29e84ed301c8d25c570300cf82b563b7961392b0 [email protected] github.com
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