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.

4 has been breached. Update your browsers! We are using 5 now :)

How do I begin? Basically, an India based company that does TLS certification published some comically bad private keys. One of which was just the character 4. Update all of your browsers btw, desktop and mobile. This is a very major low level security breech of the entire internet.

It may take Linux distros days to patch it, and this includes millions of servers.

An ssl certificate provider used 4 as their private key. This should be hundreds of characters long. Somebody figured this out and was able to issue their own certificates based on it. This results in loss of trust in their certificates which is a big deal.

It is compared as bigger than one of the largest security issues in IT the last couple of years since it forces everybody to patch their shit to not trust this certificate chain. And lots of stuff aren't patched that easily.

4

eMudhra, an Indian tech firm, had a root TLS cert with laughably low size for one of its encryption keys https://scotthelme.co.uk/eight-bits-of-trust-emudhras-ca-keys-cracked-in-milliseconds/

A company from India was issuing Internet security certificates with extremely small private keys. The lowest they issued was 4