While GitHub obsess over shoving AI into everything, the rest of the platform is genuinely crumbling and its security flaws are being abused to cause massive damage.
Last week Aqua Security was breached and a few repositories it owns were infected. The threat actors abused widespread use of mutable references in GitHub Actions, which the community has been screaming about for years, to infect potentially thousands of CI runs. They also abused an issue GitHub has acknowledged but refused to fix that allows smuggling malicious Action references into workflows that look harmless.

GHA can’t even be called Swiss cheese anymore, it’s so much worse than that. Major overhauls are needed. The best we’ve got is Immutable Releases which are opt in on a per-repository basis.

Public service announcement

You can pin actions versions to their hash. Some might say this is a best practice for now. It looks like this, where the comment says where the hash is supposed to point.