GitHub removed Node 20 from the Actions runners on 23 September 2026, and an action that declares using: node20 still doesn't fail for that: since 16 June the runner rewrites node20 to node24 before it executes anything, and it does the same with node12 and node16 . What went away on the 23rd was the escape hatch: the ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION variable no longer brings Node 20 back. The next date with real consequences is 2 November, when macos-14 is retired.

That inverts who is at risk. If your CI has been green since June without that variable, the 23rd changed nothing for you on GitHub-hosted runners. The ones that break are precisely the teams that already hit an action that can't handle Node 24, set the variable to keep moving, and filed the real fix under later.…