CVE-2026-72127 netdev-genl: report NAPI thread PID in the caller's pid namespace
A local attacker in a child PID namespace can leak global kernel thread PIDs via netdev-genl, bypassing namespace isolation.
- 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-2026-72127?
CVE-2026-72127 is a vulnerability in Linux, published on 15 Aug 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:
netdev-genl: report NAPI thread PID in the caller's pid namespace
netdev_nl_napi_fill_one() reports the NAPI kthread PID in NETDEV_A_NAPI_PID using task_pid_nr(), which returns the PID in the initial pid namespace.
NETDEV_CMD_NAPI_GET does not have GENL_ADMIN_PERM and the netdev genl family is netnsok, so a caller in a child pid namespace can issue it. That caller then sees the kthread's global PID, even though the kthread is not visible in its pid namespace, where the value should be 0.
Translate the PID through the caller's pid namespace, the same way commit 3799c2570982 ("io_uring/fdinfo: translate SqThread PID through caller's pid_ns") did for the io_uring SQPOLL thread. The doit and dumpit paths both run synchronously in the caller's context, so task_active_pid_ns(current) is the caller's pid namespace.
Which versions are affected by CVE-2026-72127?
How do I fix CVE-2026-72127?
Apply the vendor's patch.
Is CVE-2026-72127 being exploited?
There is no known exploitation of CVE-2026-72127 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72127, DEBIAN-CVE-2026-72127, GHSA-hx9w-mw8p-76q2, UBUNTU-CVE-2026-72127.