CVE-2026-93173

Published Sep 17, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: bpf,lsm: Drop bpf_prog_free from sleepable_lsm_hooks __bpf_prog_put_rcu() is the call_rcu() callback for non-sleepable programs. security_bpf_prog_free() called from there fires bpf_prog_free in softirq; if a sleepable LSM prog is attached to that hook, might_fault() BUGs: BUG: sleeping function called from invalid context in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5038 preempt_count: 101, expected: 0 Call Trace: <IRQ> __bpf_prog_enter_sleepable+0x1cd/0x320 kernel/bpf/trampoline.c:1255 bpf_trampoline_6442549705+0x53/0xd7 security_bpf_prog_free+0xde/0x130 security/security.c:5465 __bpf_prog_put_rcu+0xab/0xd0 kernel/bpf/syscall.c:2365 rcu_do_batch kernel/rcu/tree.c:2617 [inline] handle_softirqs+0x236/0x800 kernel/softirq.c:622 </IRQ> The call_rcu/call_rcu_tasks_trace split reflects the freed program's sleepability, not that of any attached observer. security_bpf_prog_free() also frees prog->aux->security, which has to stay after the grace period, so drop bpf_prog_free from sleepable_lsm_hooks rather than move the call. Non-sleepable observers still run there.

Is your site exposed to CVE-2026-93173?

Run a free security scan — no signup, results in seconds.

References

Frequently Asked Questions

What is CVE-2026-93173? +
In the Linux kernel, the following vulnerability has been resolved: bpf,lsm: Drop bpf_prog_free from sleepable_lsm_hooks __bpf_prog_put_rcu() is the call_rcu() callback for non-sleepable programs. security_bpf_prog_free() called from there fires bpf_prog_free in softirq; if a sleepable LSM prog is attached to that hook, might_fault() BUGs: BUG: sleeping function called from invalid context in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5038 preempt_count: 101, expected: 0 Call Trace: <IRQ> __bpf_prog_enter_sleepable+0x1cd/0x320 kernel/bpf/trampoline.c:1255 bpf_trampoline_6442549705+0x53/0xd7 security_bpf_prog_free+0xde/0x130 security/security.c:5465 __bpf_prog_put_rcu+0xab/0xd0 kernel/bpf/syscall.c:2365 rcu_do_batch kernel/rcu/tree.c:2617 [inline] handle_softirqs+0x236/0x800 kernel/softirq.c:622 </IRQ> The call_rcu/call_rcu_tasks_trace split reflects the freed program's sleepability, not that of any attached observer. security_bpf_prog_free() also frees prog->aux->security, which has to stay after the grace period, so drop bpf_prog_free from sleepable_lsm_hooks rather than move the call. Non-sleepable observers still run there.
How do I check if I'm vulnerable to CVE-2026-93173? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2026-93173 — free, no signup required.