Medium · CVSS 5.1CVE-2026-55222

Isar: Unprivileged user ownership of trusted repository GPG public keys storage after bootstrapCVE-2026-55222

Answer in brief

CVE-2026-55222 records a Medium severity (CVSS 5.1) vulnerability in Isar: Unprivileged user ownership of trusted repository GPG public keys storage after bootstrap. The current sources do not mark it as known exploited. The current feed maps ilbers/isar (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 23, 2026Updated Oct 23, 2026Source checked Oct 23, 2026First seen by HOL Oct 23, 2026Material review Oct 23, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.1
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 5.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps ilbers/isar (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
ilbers/isargeneric	>=0.11 <=1.1	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for ilbers/isar.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 23, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.