CVE-2026-80543
Received Received - Intake

s390/zcrypt Message Padding Fix for CCA and EP11

Publication date: 2026-08-26

Last updated on: 2026-08-26

Assigner: kernel.org

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.

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Meta Information

Published
2026-08-26
Last Modified
2026-08-26
Generated
2026-08-26
AI Q&A
2026-08-26
EPSS Evaluated
N/A
NVD
CVE-2026-80543
EUVD
EUVD-2026-66458

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel to 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (inc)

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves improper handling of messages sent to cryptographic cards. Two functions copy user space messages into kernel buffers based on message length but fail to account for a required 4-byte adjustment. This leaves up to 3 bytes of uninitialized kernel memory exposed, which could be sent to cryptographic card firmware unintentionally.

Detection Guidance

This vulnerability is specific to the Linux kernel's s390/zcrypt driver and involves uninitialized memory exposure. Detection requires checking kernel versions and configurations rather than network scanning. Examine kernel logs for zcrypt-related errors or inspect kernel memory handling in s390 systems.

Impact Analysis

An attacker with access to the system could exploit this to read sensitive kernel memory. This might expose confidential data, cryptographic keys, or other protected information processed by the kernel, potentially leading to further system compromise or data breaches.

Compliance Impact

This vulnerability could lead to unauthorized exposure of sensitive data, violating confidentiality requirements in GDPR and HIPAA. Organizations may face compliance violations, legal penalties, and reputational damage if exploited, as it undermines data protection and security controls.

Mitigation Strategies

Apply the kernel patch that pads messages with zeros. Update your Linux kernel to a version containing the fix. If immediate patching is not possible, restrict access to s390/zcrypt functionality or monitor for unusual crypto card firmware interactions.

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