{"id":"CVE-2026-98037","published":"2026-09-25T11:17:32.443","lastModified":"2026-09-25T11:17:32.443","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject untrusted allocated-object pointers\n\nWhen the final RCU read-side critical section ends, a local kptr is demoted\nto PTR_UNTRUSTED but retains MEM_ALLOC. The pointer may be NULL or may refer\nto an object whose lifetime is no longer protected.\n\ntype_is_ptr_alloc_obj() nevertheless recognizes any PTR_TO_BTF_ID with\nMEM_ALLOC as a live allocated object. In particular, a refcount-only local\nkptr never carries NON_OWN_REF, so it still passes the\nbpf_refcount_acquire() argument check after RCU protection ends. The kfunc\ncan then dereference NULL or stale memory.\n\nMake type_is_ptr_alloc_obj() reject PTR_UNTRUSTED pointers. Since\ntype_is_non_owning_ref() is based on the same predicate, graph kfunc\narguments obey the same live-object requirement. Fault-protected reads of\nthe demoted pointer remain valid: writes are already rejected, and read\nfixups use bpf_may_fault_on_deref() rather than this predicate.\n\n[ kkd: Rewrote commit log ]","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/092c2874dc1b2060fa77a465a971acd4fdf87683","tags":[]},{"url":"https://git.kernel.org/stable/c/135d542b97fa93e32c457d49d6e7b33ca7d05bae","tags":[]},{"url":"https://git.kernel.org/stable/c/6b1f786ad85a0b63393b76f5e634deab1a73198c","tags":[]},{"url":"https://git.kernel.org/stable/c/7441ee8276641bddaf1cba7bb75ef9c1458ceb3b","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}