Bug 2502284 (CVE-2026-63864)

Summary: CVE-2026-63864 kernel: bpf: Propagate error from visit_tailcall_insn
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: rhel-process-autobot, 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 Berkeley Packet Filter (BPF) verifier. The `visit_tailcall_insn` function, which is part of the BPF program validation process, failed to check and propagate error return values. This oversight could lead to an unhandled error condition within the kernel, potentially affecting system stability or integrity. The vulnerability stems from a missing error check, which is a fundamental security mechanism.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-07-19 15:01:56 UTC
In the Linux kernel, the following vulnerability has been resolved:

bpf: Propagate error from visit_tailcall_insn

Commit e40f5a6bf88a ("bpf: correct stack liveness for tail calls") added
visit_tailcall_insn() but did not check its return value.