Bug 2507218 (CVE-2026-64507)

Summary: CVE-2026-64507 kernel: x86/bugs: Enable IBPB flush on BPF JIT allocation
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
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel. This vulnerability involves an incomplete defense against Spectre-v2, a type of attack that can expose sensitive information by exploiting how modern processors predict future operations. Specifically, when the Berkeley Packet Filter (BPF) Just-In-Time (JIT) compiler was active, the system did not adequately clear the processor's branch prediction buffer during BPF JIT memory reuse. This could potentially allow an attacker to bypass existing Spectre-v2 protections, leading to the unauthorized disclosure of information.
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Description OSIDB Bzimport 2026-07-25 10:11:14 UTC 
In the Linux kernel, the following vulnerability has been resolved:

x86/bugs: Enable IBPB flush on BPF JIT allocation

Enable hardening against JIT spraying when Spectre-v2 mitigations are in
use. Specifically, issue an IBPB flush on BPF JIT memory reuse. Skip
enabling the IBPB flush if the BPF dispatcher is already using a retpoline
sequence.

This hardening applies only when BPF-JIT is in use. Guard the enabling
under CONFIG_BPF_JIT so that bugs.c still builds with CONFIG_BPF_JIT=n.
Comment 1 TEJ RATHI 2026-07-29 10:19:16 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072554-CVE-2026-64507-5288@gregkh/T