CVE-2026-98059: bpf: Mark sched_process_wait argument as nullable

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-25 · updated 2026-10-29
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Mark sched_process_wait argument as nullable do_wait() passes wo->wo_pid to the sched_process_wait tracepoint. kernel_wait4() leaves wo_pid NULL for wait4(-1), and kernel_waitid_prepare() does likewise for waitid(P_ALL). btf_ctx_access() currently types argument 0 as PTR_TO_BTF_ID | PTR_TRUSTED. Without PTR_MAYBE_NULL, the verifier accepts an unchecked dereference. Trusted pointer loads have no fault protection, so a wait for any child can then cause a NULL pointer dereference in JITed BPF code. Add sched_process_wait to raw_tp_null_args[] with argument 0 marked nullable. The verifier rejects an unchecked dereference while preserving access after the program checks the pointer for NULL.

Affected products

Linux kernel: from 6.12.6 before 6.12.111; from 6.13.1 before 6.18.53; from 6.19 before 7.2.7; 6.13-rc3, 6.13-rc4, 6.13-rc5, 6.13-rc6, 6.13-rc7, 7.3-rc1; 6.13 — fixed in 6.12.111, 6.18.53, 7.2.7
Linux kernel: from 6.12.6 before 6.12.111; 6.13 — fixed in 6.12.111, 7.3

How to fix

Upgrade to a fixed version: Linux kernel 6.12.111, 6.18.53, 7.2.7; Linux kernel 6.12.111, 7.3. Check the vendor advisory for mitigations.

References

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