Certificate authority **eMudhra** has been forced to revoke eight compromised intermediate certificates after security researchers discovered their private keys were so weak they could be recovered almost instantly. This critical flaw could have allowed attackers to forge trusted certificates for legitimate websites, enabling them to impersonate sites and intercept encrypted communications. ### The Discovery and Its Severity The weakness was first identified on October 17 by a security researcher known as **Wayne**, who was scanning publicly available certificate data. According to **Mozilla**'s incident report, all eight affected certificates used **P-384** private keys generated in April 2025 with values smaller than 256. This made them trivial to recover by testing a mere 256 possible numbers. To underscore the severity, security researcher **Flüpke** publicly shared one of the compromised private keys on **GitHub**, revealing that the private key for **eMudhra**'s "EM OV TLS CA - G3C" certificate had a value of just 4. BleepingComputer independently verified this matched a revoked certificate. ### eMudhra's Explanation and Mitigation **eMudhra** attributed the issue to an error in a script used to generate certificates in April 2025. The company stated that the error produced a second set of weaker keys, which were mistakenly selected for certificate signing due to similar labels as properly generated keys. Some of these certificates were also cross-signed by **Sectigo**. While **eMudhra** claims most affected intermediate certificates were never used in production and found no evidence of their use to issue certificates to end-users, the potential for abuse since their creation in April 2025 remains a concern. Following the disclosure, **eMudhra** revoked the eight compromised certificates and halted the issuance of new certificates under its G3 root. ### Rapid Response from Browser Makers and Software Vendors Major technology players swiftly moved to address the vulnerability: * **Mozilla** announced it blocked the compromised certificates via Firefox's **OneCRL** system on October 17, providing protection without requiring a browser update or restart. Firefox 158.0.1 and ESR updates were later released on October 20 for users with configurations preventing earlier revocation updates. * **Google Chrome** blocked the six compromised intermediates authorized to issue TLS certificates on the same day. * **Apple** implemented protections on October 19. However, software relying on its own certificate stores or not performing certificate revocation checks may continue to trust these compromised intermediates until updated. The **Go** development team has released versions 1.27.3 and 1.26.10 to address the issue, tracked as **CVE-2026-111943**. **Mozilla** cryptography engineer **Dennis Jackson** has launched an incident tracking website, `emudhra.we-have-a-problem.com`, listing affected software and available security updates. | Software | Patched version / status package consequently, administrators can use the advisory's test endpoints and mitigation instructions to verify their systems are no longer affected. It is crucial for users and administrators to install all available software updates to ensure the compromised certificates are no longer trusted.