CVE-2026-72069
CVE-2026-72069 is a security vulnerability. O3 Security confirms whether CVE-2026-72069 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
In the Linux kernel, the following vulnerability has been resolved: locking/rt: Fix the incorrect RCU protection in rt_spin_unlock() rt_spin_unlock() releases the RCU protection before…
Description
In the Linux kernel, the following vulnerability has been resolved:
locking/rt: Fix the incorrect RCU protection in rt_spin_unlock()
rt_spin_unlock() releases the RCU protection before unlocking the lock. That opens the door for the following UAF scenario:
T1 T2 spin_lock(&p->lock); rcu_read_lock(); invalidate(p); p = rcu_dereference(ptr); rcu_assign_pointer(ptr, NULL); if (!p) return; spin_unlock(&p->lock); spin_lock(&p->lock) lock(&lock->lock); rcu_read_lock(); kfree_rcu(p); rcu_read_unlock(); .... spin_unlock(&p->lock) rcu_read_unlock(); // Ends grace period rcu_do_batch() kfree(p); UAF -> rt_mutex_cmpxchg_release(&lock->lock...)
Regular spinlocks keep preemption disabled accross the unlock operation, which provides full RCU protection, but the RT substitution fails to resemble that. Same applies for the rwlock substitution.
Move the rcu_read_unlock() invocation past the unlock operations to match the non-RT semantics. This makes it asymmetric vs. rt_xxx_lock(), but that's harmless as the caller needs to hold RCU read lock across the lock operation. The migrate_enable() call stays before the unlock operation because there is no per CPU operation in the unlock path which would require migration to be kept disabled.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-72069 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-72069 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-72069. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-72069 in your dependencies?
O3 detects CVE-2026-72069 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.