CVE-2026-80546

/// Technical 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,

/// 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