CVE-2026-84042: Crun: crun: rootful krun with passt executes container payload as host root

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-10 · updated 2026-09-15
Weakness: CWE-269

Description

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

Affected products

Red Hat Enterprise Linux 10: all versions
Red Hat Enterprise Linux 9: all versions

References

https://access.redhat.com/security/cve/CVE-2026-84042
https://bugzilla.redhat.com/show_bug.cgi?id=2531222
https://github.com/containers/crun/

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