CVE-2026-74466 s390/zcrypt: Close speculative mem read possibility
A local attacker with low privileges can exploit speculative execution in the s390/zcrypt driver to read sensitive memory, requiring specific device node access.
- 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-2026-74466?
CVE-2026-74466 is a vulnerability in Linux, published on 15 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: Close speculative mem read possibility
The domain value is extracted from a given CCA or EP11 ioctl struct when a CPRB is about to be sent. Thus this is a user controlled value. Under some special conditions (custom device node used, administrative load) this value is used as an array index after bounds checking, but without speculation barrier.
Add the missing array_index_nospec() call to prevent speculative execution where this domain value is used.
Which versions are affected by CVE-2026-74466?
How do I fix CVE-2026-74466?
Apply the vendor's patch.
Is CVE-2026-74466 being exploited?
There is no known exploitation of CVE-2026-74466 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74466, DEBIAN-CVE-2026-74466, GHSA-4w55-4rvm-3v48, UBUNTU-CVE-2026-74466.