BaseFortify

Publication date: 2025-10-15

Last updated on: 2025-10-16

Assigner: kernel.org

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/[email protected]

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-10-15

Last Modified

2025-10-16

Generated

2026-07-06

AI Q&A

2025-10-15

EPSS Evaluated

2026-07-05

NVD

CVE-2025-39990

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves the BPF (Berkeley Packet Filter) subsystem where a helper function pointer could be NULL due to a disabled configuration option. The issue was that the verifier did not properly check if the helper function was valid in the get_helper_proto function. The fix involved adding a check to ensure the helper function pointer is valid and marking the tail_call helper function pointer with BPF_PTR_POISON since it is unused by design.

Impact Analysis

If exploited, this vulnerability could potentially cause the kernel verifier to behave incorrectly, possibly leading to kernel instability or security issues related to BPF programs. Since the helper function pointer could be NULL, it might cause unexpected behavior or crashes when BPF programs are verified or executed.

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