The first macOS 27.3 developer beta includes an important security fix that prevents command-line tools from accepting eMudhra's compromised web certificates. Specifically, the update removes the affected certificates from the /etc/ssl/cert.pem file.
macOS 27.3 is not expected to be released to the public until December, but a macOS 27.2.1 update will likely arrive sooner with the same security fix.
If you do not wish to update your Mac at this time, you can opt to manually remove the affected certificates from your computer's /etc/ssl/cert.pem file by following the instructions outlined in Apple's support document related to this matter.
If you do not use command-line tools via Terminal or similar, you are already fully protected. Apple said it has been blocking eMudhra's compromised TLS web certificates since October 19 in Safari, Mail, and other apps that use Apple's networking and security frameworks, across all of its software platforms. The certificates are blocked automatically with no software update required, so most users do not need to take any action.
This all comes after a security researcher last month discovered that private cryptographic keys associated with eight of Indian company eMudhra's intermediate certificate authority (CA) certificates were weak. The compromised keys could have allowed attackers to impersonate legitimate websites, potentially putting users' sensitive information at risk. So far, no evidence has surfaced that indicates the keys were exploited maliciously.
