CVE-2026-45998 rxrpc: Fix potential UAF after skb_unshare() failure
A use-after-free vulnerability in the Linux kernel's rxrpc module can cause a system crash if packet unsharing fails due to memory allocation issues.
- 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-2026-45998?
CVE-2026-45998 is a high-severity use after free vulnerability in Linux kernel, published on 27 May 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:
rxrpc: Fix potential UAF after skb_unshare() failure
If skb_unshare() fails to unshare a packet due to allocation failure in rxrpc_input_packet(), the skb pointer in the parent (rxrpc_io_thread()) will be NULL'd out. This will likely cause the call to trace_rxrpc_rx_done() to oops.
Fix this by moving the unsharing down to where rxrpc_input_call_event() calls rxrpc_input_call_packet(). There are a number of places prior to that where we ignore DATA packets for a variety of reasons (such as the call already being complete) for which an unshare is then avoided.
And with that, rxrpc_input_packet() doesn't need to take a pointer to the pointer to the packet, so change that to just a pointer.
Which versions are affected by CVE-2026-45998?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-45998?
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-2026-45998 being exploited?
There is no known exploitation of CVE-2026-45998 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-88566, BELL-CVE-2026-45998, DEBIAN-CVE-2026-45998, GHSA-mjcm-hf7x-hm3w, UBUNTU-CVE-2026-45998.