CVE-2026-97616 net/sched: act_api: release all action references on NEWACTION failure
A local attacker with high privileges can cause a resource leak in the Linux kernel traffic control subsystem, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-97616?
CVE-2026-97616 is a denial of service vulnerability in Linux, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net/sched: act_api: release all action references on NEWACTION failure
When a batched RTM_NEWACTION request replaces an existing action, tcf_idr_check_alloc() takes a temporary reference on it. If a later action fails to initialize, tcf_action_destroy() uses strict release semantics to clean up the actions initialized so far. For an action bound to a filter, the strict check returns -EPERM without dropping the temporary reference.
This error also makes tcf_action_destroy() return before releasing subsequent entries. Any new action initialized between the bound action and the failing entry is leaked together with its reserved IDR slot, preventing reuse of its index.
Use tcf_idr_release() to drop each reference held by the batch without rejecting bound actions. This allows cleanup to continue through all initialized entries and preserves the module reference release when an action is destroyed. Explicit action deletion and flushing retain their separate bind-count checks.
Which versions are affected by CVE-2026-97616?
How do I fix CVE-2026-97616?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-97616 being exploited?
There is no known exploitation of CVE-2026-97616 in the wild and no public exploit code.
Sources
Also known as AZL-104505, BELL-CVE-2026-97616, DEBIAN-CVE-2026-97616, GHSA-rpwr-33rh-mw75, UBUNTU-CVE-2026-97616.