Reported by 3 outlets
The story so far
AI summary of the reporting below · Updated · How we work
Certificate authority eMudhra has revoked eight compromised intermediate certificates after researchers discovered their private keys were remarkably weak, allowing anyone to guess them almost instantaneously. Apple, Google, and Mozilla moved rapidly to block the certificates in their root stores and browsers starting October 17. Security researcher Wayne spotted the flaw in public data, and researcher Flüpke demonstrated that the private key for eMudhra's EM OV TLS CA - G3C certificate held a value of just 4. [2][3]
According to Mozilla's incident report, the issue stems from an April 2025 script error at eMudhra that assigned P-384 private key values under 256, meaning any key could be cracked by testing only 256 possible numbers. The company mistakenly selected these weak keys for signing due to misleading labels and even submitted some to Sectigo for cross-signing. While eMudhra found no evidence that attackers exploited the flaw or that the certificates issued end-user credentials in production, adversaries theoretically had access to forge valid certificates for over a year. [3]
Mozilla protected users through its OneCRL mechanism before releasing Firefox 158.0.1, while the Go development team patched the flaw as CVE-2026-111943 in versions 1.27.3 and 1.26.10. Operating systems and developer tools including Python certifi, pip, and Ubuntu have pushed updates, though Mozilla cryptography engineer Dennis Jackson cautions that macOS's built-in curl tool and applications with custom trust stores may keep trusting the keys until manually patched. [3]
Certificate authority eMudhra revoked eight compromised intermediate certificates after researchers found their private keys were so weak that anyone could recover them almost instantly and use them to forge trusted certificates for legitimate websites.
via BleepingComputer
Private keys for eight eMudhra intermediate CA certificates have been compromised, allowing attackers to forge certificates for any site. The keys were revealed due to low entropy, not through a known breach. Browsers blocked them using revocation lists, but other software had to remove the emSign ECC G3 root. Unpatched systems remain exposed to forged certificates, including client auth and mTLS. By Chris Swan
via InfoQ
The private keys associated with eight certificates were compromised, and root programs and trust stores are blocking them.
via SecurityWeek