CVE-2026-80543 s390/zcrypt: Pad trailing CCA or EP11 message with zeros
Local attackers can read uninitialized kernel memory via s390 crypto driver due to missing padding, potentially exposing sensitive data to firmware.
- 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-2026-80543?
CVE-2026-80543 is a vulnerability in Linux, published on 26 Aug 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:
s390/zcrypt: Pad trailing CCA or EP11 message with zeros
The both functions xcrb_msg_to_type6cprb_msgx() and xcrb_msg_to_type6_ep11cprb_msgx() copy the user space message into a kernel buffer based on the message length. But on further processing the message is supposed to be 4 byte length adjusted. Thus up to 3 bytes of uninitialized kernel memory are forwarded to further processing steps and may unwanted expose kernel memory to the crypto card firmware.
This patch contains code to pad the gap between user space copied message and message buffer length sent down to further processing of the CCA or EP11 message to zeros.
Which versions are affected by CVE-2026-80543?
How do I fix CVE-2026-80543?
Apply the vendor's patch.
Is CVE-2026-80543 being exploited?
There is no known exploitation of CVE-2026-80543 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-80543, GHSA-r429-pxmh-55v9, UBUNTU-CVE-2026-80543.