Eight intermediate certificates from an Indian authority were signed with private keys so weak that a laptop could guess them by counting, letting anyone holding one stand up a site the browser trusts. Apple, Google and Mozilla have pulled their trust, but a researcher warns Macs may keep honouring the certificates anyway.
The certificates belong to eMudhra, a certificate authority in Bengaluru. Mozilla’s incident report records that all eight relied on April 2025 P-384 keys whose secret values fell below 256, narrowing guessing to a few hundred attempts. Researcher Fluepke published one recovered key showing the secret for the “EM OV TLS CA – G3C” certificate was simply 4, and BleepingComputer confirmed it matched a revoked certificate.
eMudhra told Mozilla that a fault in the generation script produced a second, weaker set of keys, picked for signing because their labels sat next to the correct ones, with some intermediates then sent to Sectigo for cross-signing. The company says most never reached production and found no sign they minted end-user certificates, though anyone could have exploited them from April 2025, with no evidence so far that anyone did.
Mozilla dropped the certificates through Firefox’s OneCRL list on October 17, needing no restart. Chrome revoked the six intermediates cleared for TLS issuance that day, and Apple applied its block on October 19. Go shipped 1.27.3 and 1.26.10 for CVE-2026-111943.
Software carrying its own trust store is where the gap sits. Cryptography engineer Dennis Jackson, who compiled a tracker of affected packages, notes macOS ships the compromised roots inside the bundle used by /usr/bin/curl, which never consults revocation data. A Mac that accepted one therefore keeps trusting it until Apple updates that file. Homebrew has rebuilt its bundle; Node.js, Debian and FreeBSD remain outstanding.
