CVE-2026-80546
Received Received - Intake

Integer Overflow in Linux Kernel s390/zcrypt Driver

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: 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.

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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-2026-80546
EUVD
EUVD-2026-66461

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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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 input validation in the s390/zcrypt component. The function xcrb_msg_to_type6cprb_msgx() has three main issues: integer overflow during 4-byte alignment, missing minimum size checks for the CPRBX structure copied from userspace, and arithmetic overflow in size calculations. These flaws can lead to undersized buffer allocations, incorrect bounds checking, and uninitialized memory access.

Detection Guidance

This vulnerability affects the Linux kernel's s390/zcrypt driver. Detection requires checking kernel versions and inspecting the zcrypt driver for improper input validation. Use commands like 'uname -r' to check kernel version and 'lsmod | grep zcrypt' to verify if the module is loaded. Review kernel logs for related errors or warnings.

Impact Analysis

This vulnerability could allow local attackers to cause buffer overflows, leading to memory corruption, privilege escalation, or denial of service. The flaws enable unauthorized memory access and potential system crashes due to improper size handling in cryptographic operations.

Mitigation Strategies

Apply the latest kernel update provided by your Linux distribution to patch the vulnerability. If immediate patching is not possible, consider disabling the zcrypt module using 'modprobe -r zcrypt' if not required. Monitor vendor advisories for updates and restrict access to systems running vulnerable kernels.

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