CVE-2026-53032: bpf: Fix NULL deref in map_kptr_match_type for scalar regs

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-24 · updated 2026-07-14
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix NULL deref in map_kptr_match_type for scalar regs Commit ab6c637ad027 ("bpf: Fix a bpf_kptr_xchg() issue with local kptr") refactored map_kptr_match_type() to branch on btf_is_kernel() before checking base_type(). A scalar register stored into a kptr slot has no btf, so the btf_is_kernel(reg->btf) call dereferences NULL. Move the base_type() != PTR_TO_BTF_ID guard before any reg->btf access.

Affected products

Linux kernel: from 6.4.16 before 6.5; from 6.5.3 before 6.6.141; from 6.7 before 6.12.91; from 6.13 before 6.18.33; from 6.19 before 7.0.10 — fixed in 6.12.91, 6.18.33, 6.5, 6.6.141, 7.0.10

How to fix

Upgrade to a fixed version: Linux kernel 6.12.91, 6.18.33, 6.5, 6.6.141. Check the vendor advisory for mitigations.

References

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