Go Issues Emergency Update Blocking Eight CA Keys Over Undisclosed Security Concerns
Oct 20, 2026
Encryption / Software Security
Go 1.27.3 and Go 1.26.10, released on October 20, make Go's certificate verifier reject any certificate chain that passes through one of eight intermediate certificate authority keys. Programs built on the new release will refuse connections to sites and services whose certificates were issued under those keys. The Go team says the keys belong to one certificate authority it has not named, and that it is blocking them because of "specific security concerns around their operation." It handled the fix on its URGENT track , the one reserved for its most serious issues, and recommends upgrading immediately. Two days earlier, on October 17, Mozilla added six intermediate certificates issued by eMudhra's emSign Root TLS CA - G3 to OneCRL , the list Firefox uses to block certificates. The Mozilla bug behind those entries is closed to the public , and neither Mozilla nor Go has said what prompted its action. Whether Chrome, Apple, or Microsoft have taken simil...