Matt M
mattm.bsky.social
Matt M
@mattm.bsky.social
I spent a bit of time poking around the Firefox codebase and filed a bug with the findings: bugzilla.mozilla.org/show_bug.cgi...

Those entries are a combination of both Kamu SM as well as roots which have been locally added to Firefox's trust store
1972339 - cert.validation_success_by_ca bin collision between CAs and unknown entries in RootCertificateTelemetryUtils.h
NEW (nobody) in Core - Security: PSM. Last updated 2025-06-16.
bugzilla.mozilla.org
June 16, 2025 at 3:01 PM
I think it’s a data error, possibly on Mozilla’s part - I found a comment suggesting bins 0 and 1 are reserved, but recently they put Kamu SM into bin 1. Maybe I’ll just exclude those suspicious bins.
June 14, 2025 at 7:19 PM
The key line here is:

> ... certificates issued on or after June 15, 2026 MUST include the extendedKeyUsage extension and only assert an extendedKeyUsage purpose of id-kp-serverAuth.
February 14, 2025 at 10:12 PM
February 4, 2025 at 10:35 PM
I think this comment really made it click for me why this is useful in a way that the docs alone hadn't!
December 17, 2024 at 5:48 PM