Bug 2568387 - CVE-2026-123876 containers-common: containers-common: default seccomp AF_VSOCK/NETLINK_AUDIT deny rules bypassable via 32-bit truncation [fedora-all]
Summary: CVE-2026-123876 containers-common: containers-common: default seccomp AF_VSOC...
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: containers-common
Version: rawhide
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Jan Kaluža
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["97895e86-24ce-4fc8-8f57-0...
Depends On:
Blocks: CVE-2026-123876
TreeView+ depends on / blocked
 
Reported: 2026-11-06 17:12 UTC by Charles Timko
Modified: 2026-11-06 17:12 UTC (History)
8 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:


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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.


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