CVE-2026-80546 s390/zcrypt: Improve CCA CPRB length and overflow checks
Integer overflows in the s390/zcrypt driver allow buffer overflows and uninitialized memory access, potentially leading to code execution or privilege escalation.
- 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-2026-80546?
CVE-2026-80546 is a high-severity 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: Improve CCA CPRB length and overflow checks
The xcrb_msg_to_type6cprb_msgx() function lacks proper input validation, creating security vulnerabilities: 1. Integer overflow after CEIL4 alignment: Signed int variables could overflow during 4-byte boundary alignment, causing undersized buffer allocations or incorrect bounds checking. 2. Missing minimum size validation: The CPRBX structure is copied from userspace without verifying sufficient buffer length. Undersized buffers cause uninitialized memory access when reading structure fields like cprbx.cprb_len and cprbx.domain. 3. Arithmetic overflow in sum calculations: Adding control block and data block sizes could overflow, bypassing size checks and enabling buffer overflows.
Fix by using size_t for length calculations, adding U32_MAX boundary checks after alignment, validating minimum control block size before copying from userspace, and detecting sum calculation overflows.
Which versions are affected by CVE-2026-80546?
How do I fix CVE-2026-80546?
Apply the vendor's patch.
Is CVE-2026-80546 being exploited?
There is no known exploitation of CVE-2026-80546 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-80546, GHSA-8cmf-4x36-qp8x, UBUNTU-CVE-2026-80546.