Bug 2568387

Summary: CVE-2026-123876 containers-common: containers-common: default seccomp AF_VSOCK/NETLINK_AUDIT deny rules bypassable via 32-bit truncation [fedora-all]
Product: [Fedora] Fedora Reporter: Charles Timko <ctimko>
Component: containers-commonAssignee: Jan Kaluža <jkaluza>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: bbaude, dwalsh, jkaluza, jnovy, nicola.sella, pholzing, rruzicka, vmiticka
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["97895e86-24ce-4fc8-8f57-0a416e15edc4"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2566536    

Description Charles Timko 2026-11-06 17:12:05 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

A flaw was found in containers-common (Podman/container-libs default seccomp profile). Deny rules for AF_VSOCK and NETLINK_AUDIT compared socket(2) integer arguments with unmasked 64-bit equality. On 64-bit architectures the kernel uses only the low 32 bits, so values such as AF_VSOCK|1<<32 bypass the deny rule while still creating the restricted socket type. This is confirmed in RHEL 9 and RHEL 10 containers-common seccomp.json. SELinux may still block some of these operations on enforcing hosts, but the seccomp profile itself does not enforce the intended restriction.