Go ships emergency update blocking eight intermediate CA keys

Go 1.27.3 and Go 1.26.10, released October 20, make the certificate verifier reject any chain passing through eight intermediate CA keys. Programs built on the new releases will refuse connections to sites and services whose certificates were issued under those keys; the Go team has not disclosed which certificate authority owns them.

• Go 1.27.3 and Go 1.26.10 were released on October 20, 2026
• Chains through any of the eight intermediate CA keys are rejected
• The Go team has not named the certificate authority or the reason