---
id: CVE-2026-80544
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  s390/zcrypt: Improve EP11 CPRB domain handling with ASN.1 parsing

  The zcrypt_msgtype6_send_ep11_cprb() function uses fragile struct
  overlays to access and modify the d…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  s390/zcrypt: Improve EP11 CPRB domain handling with ASN.1 parsing

  The zcrypt_msgtype6_send_ep11_cprb() function uses fragile struct
  overlays to access and modify the d…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 20b0b0159390fa5c00a435195649680fefda81e0 <
    00a44ff06bcffb68b9cd7e90d2259b7d14b82b18
  - >-
    Linux >= e2c6d91eb8b1533753755f07803e47eceed263d0 <
    db21b2cf6dd0af5ffd08931e0a9fcda5a0473220
  - >-
    Linux >= e2c6d91eb8b1533753755f07803e47eceed263d0 <
    0864a163783bff109b548266921829ea794edc93
  - Linux 7.1
published: '2026-08-26'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T11:17:50.770'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80544'
references:
  - url: 'https://git.kernel.org/stable/c/00a44ff06bcffb68b9cd7e90d2259b7d14b82b18'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/0864a163783bff109b548266921829ea794edc93'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/db21b2cf6dd0af5ffd08931e0a9fcda5a0473220'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00194
epssPercentile: 0.08506
ingestedAt: '2026-10-15T11:00:41.667Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

s390/zcrypt: Improve EP11 CPRB domain handling with ASN.1 parsing

The zcrypt_msgtype6_send_ep11_cprb() function uses fragile struct
overlays to access and modify the domain field in the EP11 CPRB
payload, creating maintainability and security concerns:
1. Struct overlay approach (pld_hdr) assumes fixed payload structure
   and doesn't validate the actual ASN.1 encoding.
2. Complex length format detection logic is error-prone and doesn't
   properly validate bounds at each parsing step.
3. Direct struct member access bypasses proper ASN.1 validation.

Fix by replacing struct overlays with explicit ASN.1 parsing that
validates each field (payload tag/length, function tag/length/value,
optional domain tag/length/value) with proper bounds checking at every
step. Add asn1_int_encode() helper function to safely write integer
values with correct endianness conversion. This makes the code
consistent with the validation pattern introduced with the rework of
the xcrb_msg_to_type6_ep11cprb_msgx() function.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.