CVE-2026-80545

s390/zcrypt: Improve EP11 CPRB length and overflow checks

Published Aug 26, 2026 CVSS 3.1 · 7.8 High EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

s390/zcrypt: Improve EP11 CPRB length and overflow checks

The xcrb_msg_to_type6_ep11cprb_msgx() function lacks proper input
validation, creating security vulnerabilities:
1. Missing minimum size validation: The ep11_cprb structure and
subsequent payload fields (pld_tag, pld_lenfmt) are copied from
userspace without verifying sufficient buffer length.
2. Arithmetic overflow in length calculations: CEIL4 alignment could
overflow, bypassing size checks and enabling buffer overflows.
3. The payload is asn1 encoded but the function just uses a simple c
struct overlay to access some fields of the payload.

Fix by using size_t for length calculations, adding U32_MAX boundary
checks after alignment, and validating minimum request size and
minimum reply size before copying from userspace. Do a very simple
asn1 parsing of the payload up to the function value field.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Weaknesses CWE-119
CWE-20
Type Values Removed Values Added
Weaknesses CWE-119
CWE-190
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Weaknesses CWE-119
CWE-190
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: Improve EP11 CPRB length and overflow checks The xcrb_msg_to_type6_ep11cprb_msgx() function lacks proper input validation, creating security vulnerabilities: 1. Missing minimum size validation: The ep11_cprb structure and subsequent payload fields (pld_tag, pld_lenfmt) are copied from userspace without verifying sufficient buffer length. 2. Arithmetic overflow in length calculations: CEIL4 alignment could overflow, bypassing size checks and enabling buffer overflows. 3. The payload is asn1 encoded but the function just uses a simple c struct overlay to access some fields of the payload. Fix by using size_t for length calculations, adding U32_MAX boundary checks after alignment, and validating minimum request size and minimum reply size before copying from userspace. Do a very simple asn1 parsing of the payload up to the function value field.
Title s390/zcrypt: Improve EP11 CPRB length and overflow checks
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 21, 2026, 12:46 PM
Reserved
Aug 26, 2026, 2:34 PM
Status
Received
Published
Aug 26, 2026, 3:17 PM
Modified
Oct 21, 2026, 1:19 PM
Severity
Moderate
Public date
Aug 26, 2026, 12:00 AM