CVE-2026-97618 io_uring/net: don't overconsume buffers when using MSG_TRUNC
A local attacker can cause buffer overconsumption in io_uring network operations, potentially leading to denial of service or information disclosure.
- 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-2026-97618?
CVE-2026-97618 is a vulnerability in Linux, published on 25 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:
io_uring/net: don't overconsume buffers when using MSG_TRUNC
When a recv/recvmsg is issued with MSG_TRUNC and the incoming packet is larger than the provided buffer, the net layer returns the full length of the packet rather than the number of bytes actually copied into the buffer. As a result, io_uring advances more of the provided buffer ring than was actually filled. Use the actual filled region size to consume the buffer, but still return the full size to preserve MSG_TRUNC semantics.
Take care with multishot, because that seems to already truncate the consumption based on the available payload size.
This was reported in https://github.com/axboe/liburing/issues/1619.
[axboe: fold in size_t unsigned fix]
Which versions are affected by CVE-2026-97618?
How do I fix CVE-2026-97618?
Apply the vendor's patch.
Is CVE-2026-97618 being exploited?
There is no known exploitation of CVE-2026-97618 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-97618, DEBIAN-CVE-2026-97618, GHSA-qrrw-9q98-7ph9, UBUNTU-CVE-2026-97618.