Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-08-26T00:00:00 kernel: s390/zcrypt: Improve EP11 CPRB length and overflow checks 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-120

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.

A flaw was found in the Linux kernel's s390/zcrypt component. This vulnerability stems from insufficient input validation in the `xcrb_msg_to_type6_ep11cprb_msgx()` function when handling EP11 Cryptographic Coprocessor Request Block (CPRB) messages. A local attacker could exploit this by crafting a malicious message, leading to arithmetic overflows in length calculations and subsequent buffer overflows. This could result in a denial of service or potentially allow for privilege escalation.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-80545 https://nvd.nist.gov/vuln/detail/CVE-2026-80545 https://lore.kernel.org/linux-cve-announce/2026082606-CVE-2026-80545-f190@gregkh/T