eMudhra's flawed key generation let anyone recover private keys for 8 intermediate certificates
eMudhra ignored Mozilla Root investigation deadline; blames social media
A researcher found that eight eMudhra intermediate certificates used P-384 private keys that were tiny integers, making them trivially recoverable. Mozilla independently confirmed the flaw and revoked the certificates in Firefox within hours. Six are TLS intermediates trusted by major root programs; two are code-signing certificates trusted by Microsoft. Sectigo's cross-signed versions remain unrevoked, and eMudhra has yet to answer Mozilla's root-cause questions.
The 8 impacted keys all used integers less than 256. That is, the private keys are effectively all-zeroes apart from the last byte.