bpf: Fix NULL deref in map_kptr_match_type for scalar regs
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.
02 / AFFECTED SOFTWARE
Affected packages
803 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES
Further evidence
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/0a36c1f72888bca0237295a4da19cd91821a90be
- https://git.kernel.org/stable/c/4d0a375887ab4d49e4da1ff10f9606cab8f7c3ad
- https://git.kernel.org/stable/c/520454e839710c327808c2fcc98e28cee77355fc
- https://git.kernel.org/stable/c/6982653ce5f119982aa58f1af58e7bfbebf39252
- https://git.kernel.org/stable/c/da1d615ce49a47986a8864e2371a26e97861085c
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53032.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-53032