eMudhra revokes eight TLS intermediate CAs over weak keys

What was found

On October 18, 2026, an independent security researcher reported that the keys of eight eMudhra Global TLS intermediate certificate authorities were cryptographically weak. eMudhra revoked all eight on October 19. The intermediates sit under one ECC root, which browser root programs have since distrusted.

What the company says went wrong

eMudhra says the keys were generated on FIPS 140-2 Level 3 hardware security modules, and that the failure came from one step in the key ceremony. A key wrap and unwrap step produced a second, weak set of keys next to the strong keys. The weak set was the one published to browser root stores. eMudhra says the flaw went unnoticed for about 18 months, through two independent audit cycles.

Impact as described

eMudhra says seven of the eight intermediates never entered production, and the one in production issued no certificates. It says the impact is limited to TLS certificates chaining to the distrusted root, affecting one customer ecosystem in the United States. It says its digital signature and eSign services are not affected. Cloudflare said its review found no active exploitation of the issue on its services.

Google said Chrome blocked the affected keys on October 17. It also said Chrome will remove the emSign ECC Root CA - G3 root in a release expected on October 27, 2026. Website operators with certificates chaining to that root need a certificate from another trusted hierarchy before the change takes effect.

What remains open

eMudhra's investigation is ongoing, and the company has not yet confirmed the full root cause. Accounts differ on when the first report arrived. Mozilla and Google cite October 17, while eMudhra says it learned of the issue late on October 18, India time. eMudhra says the researcher reportedly used AI-assisted tools to reverse-engineer the keys. The company says it has seen no evidence the weak keys were used before disclosure.