What’s Vulnerable › Vulnerabilities

CVE-2025-39990: bpf: Check the helper function is valid in get_helper_proto

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-10-15 · updated 2026-10-21

Description

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

Affected products

• Linux kernel: 5.8 — fixed in 6.17

How to fix

Upgrade to a fixed version: Linux kernel 6.17. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/3d429cb1278e995e22995ef117fa96d223a67e93
• https://git.kernel.org/stable/c/6233715b4b714068d6c831d214a4e8792109875a
• https://git.kernel.org/stable/c/dfbff47f120e4b0793ca0e0b8660361ccac25a74
• https://git.kernel.org/stable/c/e4414b01c1cd9887bbde92f946c1ba94e40d6d64

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