2.23.1 release notes

September 16, 2026

NGINX Instance Manager 2.23.1 release notes

Upgrade Paths

NGINX Instance Manager 2.23.1 supports upgrades from these previous versions:

• 2.20.0 - 2.23.0

If your NGINX Instance Manager version is older, you may need to upgrade to an intermediate version before upgrading to the target version.

Security updates

Important

For the protection of our customers, NGINX doesn’t disclose security issues until an investigation has occurred and a fix is available.

This release includes the following security updates:

• Instance Manager vulnerability CVE-2026-90439

  NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_v3_module module ( CVE-2026-90439).

  This issue has been classified as CWE-122: Heap-based Buffer Overflow.

Known issues

You can find information about known issues in the Known Issues topic.