CVE-2026-80544

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

s390/zcrypt: Improve EP11 CPRB domain handling with ASN.1 parsing

The zcrypt_msgtype6_send_ep11_cprb() function uses fragile struct

overlays to access and modify the domain field in the EP11 CPRB

payload, creating maintainability and security concerns:

1. Struct overlay approach (pld_hdr) assumes fixed payload structure

and doesn't validate the actual ASN.1 encoding.

2. Complex length format detection logic is error-prone and doesn't

properly validate bounds at each parsing step.

3. Direct struct member access bypasses proper ASN.1 validation.

Fix by replacing struct overlays with explicit ASN.1 parsing that

validates each field (payload tag/length, function tag/length/value,

optional domain tag/length/value) with proper bounds checking at every

step. Add asn1_int_encode() helper function to safely write integer

values with correct endianness conversion. This makes the code

consistent with the validation patte

/// 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