bpf: Check the helper function is valid in get_helper_proto
CVE-2025-39990 · published 15 Oct 2025
How serious is it
- Severity: high, CVSS score 7.8 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2025-39990?
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Who is affected
- Linux Linux: f470378c7562a2818b45ed11c98973f2b89eedd3 to < dfbff47f120e4b0793ca0e0b8660361ccac25a74, f470378c7562a2818b45ed11c98973f2b89eedd3 to < 3d429cb1278e995e22995ef117fa96d223a67e93, f470378c7562a2818b45ed11c98973f2b89eedd3 to < 6233715b4b714068d6c831d214a4e8792109875a, f470378c7562a2818b45ed11c98973f2b89eedd3 to < e4414b01c1cd9887bbde92f946c1ba94e40d6d64
- Linux Linux: 5.8
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
In the Linux kernel, the following vulnerability has been resolved:
bpf: Check the helper function is valid in get_helper_proto
kernel test robot reported verifier bug [1] where the helper func
pointer could be NULL due to disabled config option.
As Alexei suggested we could check on that in get_helper_proto
directly. Marking tail_call helper func with BPF_PTR_POISON,
because it is unused by design.
[1] https://lore.kernel.org/oe-lkp/202507160818.68358831-lkp@intel.com
Check your whole app
Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.
References
- git.kernel.org/stable/c/dfbff47f120e4b0793ca0e0b8660361ccac25a74
- git.kernel.org/stable/c/3d429cb1278e995e22995ef117fa96d223a67e93
- git.kernel.org/stable/c/6233715b4b714068d6c831d214a4e8792109875a
- git.kernel.org/stable/c/e4414b01c1cd9887bbde92f946c1ba94e40d6d64
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON