crun 1.29+ Priv Esc via PassNet (libkrun)
CVE-2026-84042 Published on September 10, 2026

Crun: crun: rootful krun with passt executes container payload as host root
A flaw was found in crun. When crun is built with libkrun and a container is started rootful with passt networking (krun.use_passt), crun can execute attacker-controlled payload from the container image with host root privileges. The issue is a regression in crun 1.29. It affects crun >= 1.29

NVD

Vulnerability Analysis

CVE-2026-84042 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.

Attack Vector:
LOCAL
Attack Complexity:
HIGH
Privileges Required:
LOW
User Interaction:
NONE
Scope:
CHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Timeline

Reported to Red Hat.

Made public.

Weakness Type

Improper Privilege Management

The software does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.


Products Associated with CVE-2026-84042

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Red Hat Hummingbird
 

Affected Versions

Red Hat Hardened Images: