https://www.theregister.com/security/2026/10/20/indian-certification-authority-emudhras-private-keys-compromised-one-of-them-was-the-number-4/5304312

It was discovered that one of India's Trusted Certificate Authorities, eMudhra, tasked with signing website certificates to verify authenticity of HTTP traffic was using the number "4" as the signing key along with 7 other keys less than 250. The key is supposed to be a unique number hundreds of binary digits long, but with such a simple key anybody can spoof a certificate that they could claim was signed by eMudhra and CA-checking lists would accept that.