---
id: CVE-2026-55222
title: >-
  Isar: Unprivileged user ownership of trusted repository GPG public keys
  storage after bootstrap
summary: >-
  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…
severity: medium
cvss: 5.1
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-1290
vendor: ilbers
product: isar
affected:
  - 'isar >= 0.11, <= 1.1'
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-23T20:43:46.972782Z'
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T20:57:39.282Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-55222'
references:
  - url: 'https://github.com/ilbers/isar/security/advisories/GHSA-rq66-pfw5-whqq'
    label: 'https://github.com/ilbers/isar/security/advisories/GHSA-rq66-pfw5-whqq'
  - url: >-
      https://github.com/ilbers/isar/commit/29e84ed301c8d25c570300cf82b563b7961392b0
    label: >-
      https://github.com/ilbers/isar/commit/29e84ed301c8d25c570300cf82b563b7961392b0
tags:
  - cve.org
ingestedAt: '2026-10-23T15:29:36.883Z'
---

## Overview

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.

## Affected

- `isar >= 0.11, <= 1.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.