Bug 2436821 (CVE-2026-23083)

Summary: CVE-2026-23083 kernel: fou: Don't allow 0 for FOU_ATTR_IPPROTO
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2026-02-04 17:05:05 UTC 
In the Linux kernel, the following vulnerability has been resolved:

fou: Don't allow 0 for FOU_ATTR_IPPROTO.

fou_udp_recv() has the same problem mentioned in the previous
patch.

If FOU_ATTR_IPPROTO is set to 0, skb is not freed by
fou_udp_recv() nor "resubmit"-ted in ip_protocol_deliver_rcu().

Let's forbid 0 for FOU_ATTR_IPPROTO.
Comment 1 Jon Moroney 2026-02-04 20:02:11 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026020422-CVE-2026-23083-8968@gregkh/T