# CVE-2026-123876: Podman: containers-common: containers-common: default seccomp af_vsock/netlink_audit deny rules bypassable via 32-bit truncation

Status: published. Published: 2026-11-06. Updated: 2026-11-06.

A flaw was found in the default seccomp profile used by Podman via containers-common. Deny rules for AF_VSOCK and NETLINK_AUDIT compared socket arguments with unmasked 64-bit equality. Because the kernel truncates those int arguments to 32 bits, setting upper bits can bypass the deny rules.

## Remediation

- workaround: Enforcing SELinux may still deny vsock; do not rely on the unfixed seccomp denies; ship SCMP_CMP_MASKED_EQ profile updates. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 10 (containers-common): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (container-tools:rhel8/containers-common): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (containers-common): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Hardened Images (containers-common): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Hardened Images (podman): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Hardened Images (skopeo): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (containers-common): 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: 4.4 (medium); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-184

## Exploit evidence

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

## References

- https://access.redhat.com/security/cve/CVE-2026-123876 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2566536 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://github.com/podman-container-tools/container-libs/issues/1248 (CNA: redhat)

- https://github.com/podman-container-tools/container-libs/pull/1249 (CNA: redhat)

- https://www.openwall.com/lists/oss-security/2026/10/27/3 (CNA: redhat)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-123876; retrieved 2026-11-06; source updated 2026-11-06

Revision: 823e688f48d8ce0e32d79c3dd98327de7639925d43745a43a68aed389154d21c

Canonical: https://y2.dev/cve/CVE-2026-123876

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