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

highCVSS 7.1CVE-2026-68453

CSIRTS triage

vendor: Linux product: Linux Kernel Memory corruption

What: The s390/zcrypt driver's cca_cipher2protkey function reads beyond allocated buffer boundaries.
Who is affected: IBM System z (s390) systems running Linux with zcrypt enabled.
Urgency: High priority; CVSS 7.1 indicates high severity and information disclosure through over-read.
Action: Apply Linux kernel patch to fix buffer over-read in s390/zcrypt cca_cipher2protkey function.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.1
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68453

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-684530.13% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-68453	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for s390/zcrypt

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownCVE-2026-74466: In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: Close specula…nvd · 2026-08-15
highCVE-2026-68453: In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: Fix buffer ov…nvd · 2026-08-13
highCVE-2026-68452: In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: Validate leng…nvd · 2026-08-13
highCVE-2026-68451: In the Linux kernel, the following vulnerability has been resolved: s390/zcrypt: Validate leng…nvd · 2026-08-13
mediumCVE-2026-68452: s390/zcrypt: Validate length for CCA AES cipher key requestsmsrc · 2026-08-11
highCVE-2026-68451: s390/zcrypt: Validate length for CCA ECC private key requestsmsrc · 2026-08-11