CVE-2026-80710

Received Received - Intake

s390/dasd Format-Check Buffer Overflow Fix

Publication date: 2026-08-28

Last updated on: 2026-08-29

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: s390/dasd: Fix undersized format-check buffer fmt_buffer_size in dasd_eckd_check_device_format() is declared as int, even though one of the multiplicands, sizeof(struct eckd_count), is a size_t. The expression trkcount * rpt_max * sizeof(struct eckd_count) is therefore correctly evaluated at 64-bit width, but the result is silently truncated when it is stored back into the 32-bit fmt_buffer_size variable. For a sufficiently large track range (start_unit/stop_unit are caller-controlled) this truncation yields a buffer size far smaller than the number of tracks actually requested. kzalloc() then succeeds with an undersized allocation, while the subsequent channel program build still operates on the untruncated track count and writes past the end of that buffer. Compute the buffer size with check_mul_overflow() and keep it in a size_t, so that a value that no longer fits results in -EINVAL instead of a silently truncated allocation size.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-28

Last Modified

2026-08-29

Generated

2026-09-17

AI Q&A

2026-08-28

EPSS Evaluated

2026-09-15

NVD

CVE-2026-80710

EUVD

EUVD-2026-67445

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a buffer overflow vulnerability in the Linux kernel's s390/dasd driver. It occurs when calculating a buffer size for device format checks. The calculation uses a 32-bit integer for a value that should be 64-bit, causing silent truncation. This leads to an undersized memory allocation that can be overflowed during subsequent operations.

Detection Guidance

This vulnerability is specific to the Linux kernel's s390/dasd driver and does not have a direct network detection method. Detection requires checking the kernel version and verifying if the vulnerable code path is present. Use uname -a to check the kernel version and grep for the affected driver in the kernel source or running system.

Impact Analysis

An attacker with access to trigger this condition could cause memory corruption, leading to system crashes or potentially arbitrary code execution. This requires local access to exploit and could impact system stability or security if unpatched.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a low-level kernel buffer overflow issue in the Linux S390 DASD driver that could lead to memory corruption or crashes, but there is no evidence it involves data exposure or privacy violations.

Mitigation Strategies

Apply the latest kernel update provided by your Linux distribution to patch the vulnerability. If an update is not immediately available, consider disabling the s390/dasd driver if not in use or restrict access to affected systems until patched.

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