VulnerabilityPublished 25 Jul 2026Updated 19 Aug 2026

CVE-2026-64508: Linux kernel · bpf: Support for hardening against JIT spraying

Source GCVE Database

Not known to be exploited.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-667g-8hv2-vmxj

What to do

AI-suggested

A fix has been implemented in the Linux kernel that flushes indirect branch predictors before reusing JIT memory, preventing reuse of stale branch predictions. This fix is architecture-dependent and applies to allocations within certain size bounds. Users should update to a Linux kernel version that includes this patch to ensure protection. Patch status is not explicitly stated in the provided data; therefore, check the official Linux kernel advisories or vendor updates for the exact fixed versions and apply them accordingly.

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.

Impact

This vulnerability could allow an attacker to exploit branch prediction reuse in the BPF JIT allocator, potentially facilitating JIT spraying attacks. Such attacks might undermine kernel security by enabling code reuse or bypassing certain mitigations. However, the fix has been implemented in the Linux kernel to flush branch predictors on JIT memory reuse, reducing the risk. There are no known exploits in the wild at this time.

Summary

The Linux kernel's BPF JIT allocator packs multiple small programs into larger executable memory allocations and reuses space as programs are loaded and freed. Without flushing indirect branch predictors, indirect jumps into newly written programs could reuse branch prediction data from previously resident code, enabling a form of JIT spraying attack. The vulnerability is mitigated by introducing a static key and call to flush branch predictors on JIT memory reuse. Architectures requiring this flush can implement it, while others default to a no-operation. Allocations larger than a pack are not flushed, which is considered safe due to bounded sizes of unprivileged cBPF programs. A warning is issued if assumptions about program sizes are violated when the flush is active.

References

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