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.
Advisories

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Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 28 Aug 2026 17:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-190

Fri, 28 Aug 2026 13:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-122

Fri, 28 Aug 2026 10:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-122

Fri, 28 Aug 2026 07:30:00 +0000

Type Values Removed Values Added
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.
Title s390/dasd: Fix undersized format-check buffer
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-28T06:53:10.028Z

Reserved: 2026-08-26T14:34:25.787Z

Link: CVE-2026-80710

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-28T08:16:56.633

Modified: 2026-08-28T08:16:56.633

Link: CVE-2026-80710

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-28T17:00:13Z

Weaknesses