Live › vulnerability › CVE-2026-98952
Go to dashboardThe Linux kernel's PFCP tunnel receive path reads an 8-byte session ID beyond the end of short or fragmented packets when the S flag is set. The out-of-bounds data is stored in tunnel metadata that flower classification later uses.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Systems running a Linux kernel with the PFCP (pfcp) encapsulation driver in use, where PFCP tunnels receive traffic from the network. The sources do not say which kernel versions are fixed or whether the driver is built in by default, so unknown.
No product ranges from the sources yet.
Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
In the Linux kernel, the following vulnerability has been resolved:
pfcp: make sure the SEID is linear before reading it
pfcp_encap_recv() only makes sure that the UDP header and the 4 byte PFCP header are in the linear area. When the S flag is set, pfcp_session_recv() then reads the 8 byte SEID that follows, which is not covered by the pskb_may_pull() check.
A short PFCP packet with the S flag set, or one whose session header lies in a fragment, therefore makes pfcp_session_recv() read beyond the end of the packet data, and whatever it finds there is stored in the tunnel metadata that flower later classifies on.
Pull up to the end of the SEID before reading it, and drop packets that are too short to contain it. Reload the header pointer afterwards since pskb_may_pull() may reallocate the skb head.
Use offsetofend() rather than sizeof(struct pfcphdr_session): the structure is not packed, so its size is 16 bytes because of the alignment of the __be64 member, while the header on the wire is only 12 bytes, and valid session messages would be dropped.
This page as .md · .json · in your agent: get_signal("CVE-2026-98952")
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