CVE-2026-97616: net/sched: act_api: release all action references on NEWACTION failure
In the Linux kernel, the following vulnerability has been resolved:
net/sched: actapi: release all action references on NEWACTION failure
When a batched RTMNEWACTION request replaces an existing action, tcfidrcheckalloc() takes a temporary reference on it. If a later action fails to initialize, tcfactiondestroy() 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 tcfactiondestroy() 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 tcfidrrelease() 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.
Affected Software
Event History
Frequently Asked Questions
Which action-update sequence can trigger the resource leak?
It occurs when a batched RTM_NEWACTION request replaces an existing action, that action is bound to a filter, and a later action in the same batch fails to initialize. Actions initialized after the bound action and before the failing entry can be left referenced with their IDR slots reserved.
What is the practical impact of a failed batch?
Leaked actions retain reserved IDR slots, preventing reuse of their indexes. Cleanup can also stop before processing later initialized entries in the batch.
Does this change the handling of explicit action deletion or flushing?
No. Explicit action deletion and action flushing retain their separate bind-count checks; the change applies to cleanup of references held during failed batched NEWACTION processing.