# CVE-2026-68453: s390/zcrypt: Fix buffer over-read in cca_cipher2protkey

CVE-2026-68453 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-68453, released August 16, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-68453
- Priority: High
- CVSS: 7.1 (Important)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 13, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68453

## Description

In the Linux kernel, the following vulnerability has been resolved:  s390/zcrypt: Fix buffer over-read in cca_cipher2protkey  Add validation of both the actual key buffer size and token length fields in all the cca_check_sec*token() functions. Additionally check in cca_gencipherkey() for possible underflow with returned key size.  The CCA token structures contain user-controlled len fields that were used in operations without proper validation against both the actual buffer size and minimum token structure size. An attacker could set this field larger than the actual buffer size, leading to reading beyond buffer boundaries. This may result in a kernel crash or exposure of memory via sending this as part of a request down to the crypto card. Also an attacker could have used a very small len value and thus enforce a buffer under-run which may produce similar effects as a over-read.  So now a key must - key buf length must be at least sizeof the token struct - the key len field inside the token must fit into the range of   sizeof key token struct ... key buf length

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.115-2 | [DEBIAN-CVE-2026-68453](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68453.md) | Aug 16, 2026 |
| Linux | linux Debian 14 | 7.1.8-1 | [DEBIAN-CVE-2026-68453](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68453.md) | Aug 16, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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