CVE-2026-43502 net/rds: handle zerocopy send cleanup before the message is queued
A memory leak in the Linux kernel RDS module occurs during zerocopy send failures, potentially leading to resource exhaustion and denial of service.
- 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-2026-43502?
CVE-2026-43502 is a high-severity memory corruption vulnerability in Linux kernel, published on 21 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:
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.
Weakness: CWE-401
Which versions are affected by CVE-2026-43502?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43502?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-43502 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43502 exists.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-87075, BELL-CVE-2026-43502, DEBIAN-CVE-2026-43502, GHSA-mhq7-fqmq-29pq, ROOT-OS-DEBIAN-11-CVE-2026-43502, ROOT-OS-DEBIAN-12-CVE-2026-43502 and 3 more.