CVE-2026-93288 netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state
A use-after-free vulnerability in the Linux kernel netfilter subsystem allows attackers to cause denial of service or potentially execute code.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93288?
CVE-2026-93288 is a high-severity use after free vulnerability in Linux, published on 24 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:
netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state
sashiko reports: "nfnl_log_net_exit() calls nf_log_unset(), which clears the logger pointer without an RCU grace period. Immediately after, ops_free_list() frees the per-net state while concurrent packets might still be executing nf_log_packet() under rcu_read_lock()."
Clear the pointer via .pre_exit to make sure rcu readers have completed before pernet storage is free'd. The change in nf_log_syslog.c is only done for consistency: it doesn't use pernet data.
Which versions are affected by CVE-2026-93288?
How do I fix CVE-2026-93288?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-93288 being exploited?
There is no known exploitation of CVE-2026-93288 in the wild and no public exploit code.
Sources
Also known as AZL-103958, BELL-CVE-2026-93288, DEBIAN-CVE-2026-93288, GHSA-56j7-mrx8-v649, UBUNTU-CVE-2026-93288.