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

Status: published. Published: 2026-09-10. Updated: 2026-11-04.

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

## Remediation

- workaround: Do not run untrusted images with krun and passt until a fixed crun is released. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 10 (crun): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (container-tools:rhel8/crun): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (crun): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Hardened Images (crun): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (crun): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-8): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 5 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 7.8 (high); CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 0.10% as of 2026-11-04; percentile 0.83%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-269

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2026-84042 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2531222 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://github.com/containers/crun/ (CNA: redhat)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-84042; retrieved 2026-11-05; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-84042; retrieved 2026-11-05; source updated Not reported

Revision: f81b057b7862acabe8d0e3dcda1437eee9bdc8afabdccbdf3e1c024f9b73dc07

Canonical: https://y2.dev/cve/CVE-2026-84042

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