CVE-2026-97616

What the bug is

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.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

net/sched/act_api.c

What this is

TC subsystemMAINTAINERS section matched on net/sched/ · netdev@vger.kernel.org · Maintained

Check it on the machine

grep -w CONFIG_NET_CLS_ACT /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

Show whether Debian builds this, per release

Debian builds this code. Every release below compiles the affected file into the kernels it ships.

• bookworm, trixie, forky, sid, bookworm · linux-6.12y

y

built into the kernel image on every flavour - only a patch removes it

Build switch

CONFIG_NET_CLS_ACT

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-09-25 (24 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.20%, higher than 9.2% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

net/sched

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
3.15	6.12.111	f908c8a96994
3.15	6.18.53	64b36eaef6ea
3.15	7.2.7	048617743feb
3.15	7.3	478eb5abb519

Debian advisories