CVE-2026-64508

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Support for hardening against JIT spraying The BPF JIT allocator packs many small programs into larger executable allocations and reuses space within those allocations as programs are loaded and freed. When fresh code is written into space that a previous program occupied, an indirect jump into the new program can reuse a branch prediction left behind by the old one. Flush the indirect branch predictors before reusing JIT memory so that indirect jumps into a newly written program don't reuse predictions from an old program that occupied the same space. Introduce bpf_arch_pred_flush_enabled static key and bpf_arch_pred_flush static call for flushing the branch predictors on JIT memory reuse. Architectures that need a flush, can update it to a predictor flush function. By default, its a NOP and does not emit any CALL. Allocations larger than a pack are not covered by this flush. That is safe because cBPF programs (the unprivileged attack surface) are bounded well below a pack size. Issue a warning if this assumption is ever violated while the flush is active.

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EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.11%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/6e52c240c43a601b681e3a4e58fc5685114d4726 https://git.kernel.org/stable/c/7a6c171c6a1ac6d1509752dac131d941a3de0b37 https://git.kernel.org/stable/c/8ff183ee4d8c452960df58175a094828c0513b2e https://git.kernel.org/stable/c/96cce16e26dd02a8678f1e87f88a4b5cdb63b995 https://git.kernel.org/stable/c/eed774da601268dae674e14d54a15e3624691f52

Frequently Asked Questions

What is CVE-2026-64508? +

In the Linux kernel, the following vulnerability has been resolved: bpf: Support for hardening against JIT spraying The BPF JIT allocator packs many small programs into larger executable allocations and reuses space within those allocations as programs are loaded and freed. When fresh code is written into space that a previous program occupied, an indirect jump into the new program can reuse a branch prediction left behind by the old one. Flush the indirect branch predictors before reusing JIT memory so that indirect jumps into a newly written program don't reuse predictions from an old program that occupied the same space. Introduce bpf_arch_pred_flush_enabled static key and bpf_arch_pred_flush static call for flushing the branch predictors on JIT memory reuse. Architectures that need a flush, can update it to a predictor flush function. By default, its a NOP and does not emit any CALL. Allocations larger than a pack are not covered by this flush. That is safe because cBPF programs (the unprivileged attack surface) are bounded well below a pack size. Issue a warning if this assumption is ever violated while the flush is active.

How do I check if I'm vulnerable to CVE-2026-64508? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.