IBM z/OS 3.1 End of Life Date
IBM z/OS 3.1 end-of-life date, support status, and CVE risk. Dates read at the vendor's own lifecycle pages (ibm.com); the source of each date is on the product page.
IBM z/OS 3.1 was released on September 29, 2023 and has no published end-of-life date yet. Its most recent patch is 3.1.0, published September 29, 2023.
What does IBM z/OS 3.1 end of life mean?
When IBM z/OS 3.1 reaches end of life, the maintainers stop issuing security patches for this version. CVEs discovered after the EOL date are publicly disclosed on the National Vulnerability Database with no patch available. Exploit code frequently appears on GitHub within days of disclosure.
The CVE blind spot: A CVE-based scan does not show the ongoing accumulation of unpatched vulnerabilities in EOL software versions. Some scanners flag unsupported versions of common products, but coverage varies, and none of them give you the date in advance. Running IBM z/OS 3.1 past its EOL date creates a growing attack surface that a clean scan result does not rule out.
Migrate to IBM z/OS 3.2 or implement compensating controls — network segmentation, enhanced monitoring, restricted access — while migration is underway.