CVE-2026-90317 — bpf: Invalidate RCU pointers after final spin unlock
In the Linux kernel, the following vulnerability has been resolved: bpf: Invalidate RCU pointers after final spin unlock In a sleepable BPF program, a spin lock can provide th…
Published: 2026-09-17 · CVSS: 7.8 · CVSS 3.1
In the Linux kernel, the following vulnerability has been resolved: bpf: Invalidate RCU pointers after final spin unlock In a sleepable BPF program, a spin lock can provide the only RCU protection for a kptr. The final bpf_spin_unlock() ends that protection, but the verifier leaves the pointer valid. Another CPU can then free the object before the pointer is used. A capability-limited runtime PoC triggered a task_struct use-after-free in __bpf_get_task_stack(). Record whether the program is in an RCU-protected context before releasing the lock. Invalidate RCU-protected pointers only when the unlock leaves the final such context. This preserves valid pointers in non-sleepable programs and inside an explicit RCU read-side section.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7