CVE-2026-43502

/// Technical description

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

net/rds: handle zerocopy send cleanup before the message is queued

A zerocopy send can fail after user pages have been pinned but before

the message is attached to the sending socket.

The purge path currently infers zerocopy state from rm->m_rs, so an

unqueued message can be cleaned up as if it owned normal payload pages.

However, zerocopy ownership is really determined by the presence of

op_mmp_znotifier, regardless of whether the message has reached the

socket queue.

Capture op_mmp_znotifier up front in rds_message_purge() and use it as

the cleanup discriminator. If the message is already associated with a

socket, keep the existing completion path. Otherwise, drop the pinned

page accounting directly and release the notifier before putting the

payload pages.

This keeps early send failure cleanup consistent with the zerocopy

lifetime rules without changing the normal queued completion path.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References