CVE-2026-99264

Status: UPDATED  |  Advisory ID: CVE-2026-99264

Key Details

Affected Products, Subsystems & Sectors

What to Know

In the Linux kernel, the following vulnerability has been resolved:

io_uring/net: don't retry recv on uncommitted buffers

Commit 41b70df5b38b ("io_uring/net: commit partial buffers on retry")

commits ring provided buffers when a receive is going to be retried after

a partial transfer, so that another request using the same buffer group

can't be handed the memory the first one keeps receiving into. It commits

the number of bytes received so far. That does the job for a single

buffer which is consumed as a whole, but the request hangs on to all it

has mapped:

- For a buffer ring with IOU_PBUF_RING_INC only these bytes are consumed.

The rest of the buffer stays at the head of the ring.

- For a bundle only the buffers which hold these bytes are consumed, the

others that were peeked stay in the ring.

In both cases the next receive with that buffer group gets memory that

the retried request is still going to write to, and whoever comes last

overwrites the data of the other. What the retry fills isn't committed at

all, as the buffer list isn't known any more at that point. So the kernel

hands it out again later on, while the CQE tells the application that it

was used, and for an incremental buffer that it is done with.

The remainder can't be committed in advance: if the request ends up

receiving less, there is no way to tell the application that more was

consumed than the CQE accounts for. Complete the request with what it has

got instead of retrying it. MSG_WAITALL is no longer honoured for

receives into incremental buffers or multi buffer bundles, they can

return a short count, with the request marked as failed like for other

short MSG_WAITALL transfers. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References