NetBSD 9.5 has been released as the final version of this aging stable branch

The NetBSD Project has announced the release of NetBSD 9.5, the fifth and final installment from the NetBSD 9 stable branch. Unveiled on August 31, 2026, the update bundles a curated set of security and stability fixes accumulated since the release of NetBSD 9.4 in April 2024, and remains fully compatible with NetBSD 9.0. According to the announcement published by developer Martin Husemann, the release was assembled from a selected subset of changes deemed critical for security and stability.

The update packs a substantial roster of fixes, particularly in the networking stack. Among the notable changes are a fix for a remotely triggerable null pointer dereference in ICMPv6 parsing in ipf, a plug for a four-byte kernel stack data leak through TCP timestamps, and a mitigation for the so-called TCP SegmentSmack attack. Storage reliability also gets attention, with a fix addressing possible ZFS data corruption during FIOSEEKDATA/FIOSEEKHOLE operations. On the hardware front, the release adds support for a range of newer USB devices, including Brainboxes USB-to-serial adapters and Mercusys and Asus USB Wi-Fi adapters, alongside repairs to thread-local storage on aarch64 systems and brightness controls on select ACPI-equipped machines.

Notably, the release doubles as a retirement notice: NetBSD 9.5 marks the end-of-support for the entire NetBSD 9 branch, and the project stresses there will be no further security pullups to it. Users still running NetBSD 9 in production are urged to migrate to a newer release series, such as NetBSD 11.0, with version 11.1 expected at the end of September, or NetBSD 10.2, which is slated for release within days. The full release notes and download links are available on the NetBSD website.