Bug 2541218 (CVE-2026-98060)

Summary: CVE-2026-98060 kernel: bpf: Reject resilient lock operations in rbtree callbacks
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. A local user with permissions to load Berkeley Packet Filter (BPF) programs can cause a Denial of Service (DoS) or potentially achieve privilege escalation. The BPF verifier fails to prevent resilient lock operations within red-black tree comparison callbacks, allowing a callback to improperly release the tree lock during an active traversal. Consequently, another processor can remove and free the node, causing the kernel to access freed memory.
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Description OSIDB Bzimport 2026-09-25 11:04:36 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bpf: Reject resilient lock operations in rbtree callbacks

__bpf_rbtree_add() keeps parent and link pointers live across calls to the
program-supplied comparison callback. The verifier therefore requires the
root's lock to remain held throughout the callback.

The helper path enforces this rule for bpf_spin_lock() and
bpf_spin_unlock(), but the resilient lock kfunc argument path does not.
Since resilient locks may protect BPF rbtree roots, a callback can release
the root lock and let another CPU remove and free the node referenced by
the in-progress tree walk. The walk then resumes using freed pointers.

Reject resilient lock kfuncs in an rbtree comparison callback, matching
the existing policy for the spin lock helpers. Resilient-lock-protected
trees remain valid when their comparison callbacks leave lock state alone.
Comment 1 Keith Grant 2026-09-29 00:02:42 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98060.mbox