Bug 2554986 (CVE-2026-98589)

Summary: CVE-2026-98589 kernel: bpf: Reject pkt arguments in mutating subprogs
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) verifier. When packet pointers are passed into subprograms that mutate packet data, the verifier incorrectly assumes the underlying memory remains valid across calls, failing to account for operations that invalidate or relocate packet buffers. A local user with permissions to load BPF programs can exploit this flaw to cause memory corruption, potentially leading to a Denial of Service (DoS) or privilege escalation.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-10-18 15:37:33 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bpf: Reject pkt arguments in mutating subprogs

The verifier tracks changes in how PTR_TO_PACKET registers'
bounds are modified across subprog boundaries. PTR_TO_PACKET
registers are actually passed as PTR_TO_MEM, which is assumed
valid for the entire call. This is not the case with packet memory,
where a pskb_* call may invalidate its memory region.

Reject BPF code that passes PTR_TO_PACKET pointers to subprogs that
may mutate a packet. We cannot pass the pointer as a true PTR_TO_PACKET
because we would also need to somehow pass the PTR_TO_PACKET_META
or PTR_TO_PACKET_END to the subprog. Since we cannot avoid representing
the pointer in the subprog as PTR_TO_MEM, only permit it if the
subprog is guaranteed not to mutate the packet.