CVE-2026-90113 netdevsim: update queue NAPI association on queue reset
A use-after-free in the Linux kernel netdevsim driver allows local attackers to cause a crash or read memory via Netlink queue dumps after a queue reset.
- 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-2026-90113?
CVE-2026-90113 is an use after free vulnerability in Linux, published on 17 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:
netdevsim: update queue NAPI association on queue reset
In netdevsim, receive queues (struct nsim_rq) embed their own struct napi_struct. When queue reset is performed (e.g. via queue_reset debugfs), nsim_queue_start() swaps in a newly allocated struct nsim_rq, and nsim_queue_mem_free() later deletes and frees the old one.
However, nsim_queue_start() failed to update the queue-to-NAPI mapping via netif_queue_set_napi(). As a result, dev->_rx[idx].napi continued to point to the old NAPI struct. After the old queue was freed, a subsequent queue dump via Netlink (NETDEV_CMD_QUEUE_GET) triggered a KASAN slab-use-after-free read in nla_put_napi_id() when accessing rxq->napi->napi_id.
Fix this by calling netif_queue_set_napi() in nsim_queue_start() to associate the new NAPI with the RX queue, and clear the association with netif_queue_set_napi(..., NULL) in nsim_del_napi() during teardown.
Which versions are affected by CVE-2026-90113?
How do I fix CVE-2026-90113?
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-2026-90113 being exploited?
There is no known exploitation of CVE-2026-90113 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-90113, DEBIAN-CVE-2026-90113, GHSA-wx7j-g336-w48j, UBUNTU-CVE-2026-90113.