On October 22, 2026, eMudhra said it was making Sectigo-issued certificates available as an alternative for all customers, after revoking eight compromised intermediate certificate authority (CA) certificates on October 18. The eight intermediates covered six TLS certificates and two for code signing. eMudhra says none issued end-entity certificates, the certificates issued to websites or software publishers.
What was compromised
The affected private keys belonged to eight intermediate CAs, which can issue end-entity certificates. Mozilla’s incident record places their generation in a ceremony on April 30, 2025, as part of a batch of 24 subordinate CAs.
Researcher Wayne reported the compromise on October 17, 2026. Mozilla independently recovered all eight P-384 private keys. The private values were integers below 256, making them recoverable almost instantly, according to Mozilla. The flaw was in key generation, not in the P-384 cryptographic algorithm.
In its October 21 account, eMudhra described a deviation in a wrap/unwrap test that generated a second, weak key pair. Similar labels led to the weak pair being selected for certificate signing requests (CSRs). The company said it had not yet confirmed the exact root cause.
What eMudhra said about certificates and customers
eMudhra said seven of the eight intermediates were never used in production. The eighth was deployed but issued no end-entity certificates. The company separately reported that distrust of the associated emSign ECC Root CA - G3 affected one U.S. customer ecosystem and that the customer’s certificates were being replaced.
A Mozilla Certificate Transparency snapshot from October 21, 2026, counted about 30,800 unexpired precertificates chaining to that root. Of these, 30,791 were issued by two Internet2/InCommon subordinate CAs, and 18 by eMudhra intermediates. The figures describe the wider population under the root, alongside the separate customer impact eMudhra reported.
The company also said its digital-signature and eSign services, emSigner, CertiNext, emCA, Privatrust, and SecurePass ran on separate infrastructure and were unaffected.
Why software outside browsers matters
A trust store is the set of certificates a program accepts as trusted. Applications can manage their own trust stores and revocation checks, so browser protections do not necessarily apply to every TLS client.
Cisco Talos identified VPNs, enterprise network appliances, build systems, package managers, and embedded systems as places where separate or stale trust stores may matter. Talos said Go versions 1.27.3 and 1.26.10 filter certificate chains containing the eight affected SPKI SHA-256 hashes under CVE-2026-111943. Operators should assess the trust store and revocation behavior of each TLS client and apply relevant vendor updates.
Cisco Talos reported that it had observed no malicious incidents involving the certificates in the wild as of October 21, 2026, at 14:00 UTC.
