eMudhra Certificates: Check Your Site Before November 16

As of Friday, November 13, 2026, major browsers and operating systems have already blocked a set of compromised eMudhra intermediate digital certificates, have removed or scheduled the removal of related eMudhra root certificates, and have set upcoming deadlines that can cause a website to show a security warning if it still uses an affected certificate. eMudhra, an Indian digital trust company, has also said it is withdrawing from the global SSL/TLS certificate business.

SSL/TLS certificates are the credentials a website or app presents so browsers and other software can confirm they are connecting to the real service and that the connection is encrypted. They are often issued under a brand name such as emSign, which is eMudhra's certificate brand.

The short version: check whether your website, email, or other internet-facing service uses a certificate that chains to an eMudhra or emSign root, especially emSign ECC Root CA - G3 or emSign Root CA - G1. If it does, replace it with a certificate from another trusted provider. Do not wait for the current certificate to expire. The most immediate deadline is Monday, November 16, 2026, when Microsoft says it will start removing remaining eMudhra roots from Windows, Microsoft Edge, and related services.

What happened

On Saturday, October 17, 2026, a security researcher reported that the private keys for eight eMudhra intermediate certificate authorities were weak enough to be recovered. Mozilla says it received the report at 20:06 UTC (3:06 PM Central Time). Google says the Chrome Root Program received the report at 18:05 UTC (1:05 PM Central Time) and, after confirming the findings, issued a Chrome block at 19:45 UTC (2:45 PM Central Time) the same day. Six of the eight intermediates were used for website (TLS) certificates, and two were used for code signing.

Those keys are supposed to be secret. If they can be reconstructed, someone could create a certificate that looks legitimate for a website or service they do not control. Google describes the cause as insufficient randomness (weak cryptographic entropy) when the keys were generated. eMudhra has said a flaw in a key-generation ceremony on April 30, 2025, produced a second set of weak keys, and that those weak keys were the ones published to browser root stores. eMudhra says its infrastructure was not compromised, no data was breached, and no end-entity certificates were issued from the eight affected intermediates. Google has said that, as of its October 20 announcement, no TLS certificates chaining to those six intermediates had been logged to Certificate Transparency before Chrome's block, so no fraudulent certificates from those intermediates could have been used against software that requires Certificate Transparency, including Chrome.

Mozilla says it blocked the affected certificates in Firefox through OneCRL, and that by 22:59 UTC (5:59 PM Central Time) on October 17 the update had reached Firefox users with standard settings, without a browser restart. Google issued a similar Chrome CRLSet update the same day. Apple says it automatically blocks the affected TLS intermediate certificates and the emSign ECC Root CA - G3 root in Safari, Mail, and apps that use Apple's networking and security frameworks. Microsoft says it published a Windows Disallowed Certificate Trust List update on October 20 and a separate Microsoft Edge and WebView2 update to block the affected authorities.

On October 20, Mozilla also removed the root that had signed the affected intermediates, emSign ECC Root CA - G3, from its NSS trusted-certificate list (NSS 3.131.1), and released Firefox updates to cover users whose settings may have blocked the OneCRL update. Google removed the same root from the Chrome Root Store and said that removal was expected to reach all devices that rely on that store on the morning of Tuesday, October 27, 2026, Pacific Time. Microsoft said that on October 26 it released a Windows update removing seven certificates associated with the affected hierarchies (six eMudhra G3 roots and an AAA Certificate Services cross-sign), and that on October 27 it removed the same seven from the Microsoft Edge trust list.

On October 22, 2026, eMudhra announced that its board had decided to withdraw from the global SSL/TLS certificate business. It said it would replace affected customers' certificates at no cost through partners, keep revocation and certificate-status services running until every issued certificate has expired or been replaced, and continue serving customers from its G1 RSA roots until the transition is complete. It also said its other businesses, including digital signature certificates, eSign, and enterprise PKI products, run on separate infrastructure and were not affected. Reuters reported the exit the same day.

Dates that still matter

As of November 13, 2026, certificates that chain only to the already-removed G3 root should already fail in current browsers. Certificates that still chain to remaining eMudhra roots, including emSign Root CA - G1, are now approaching further cutoffs. The dates do not all mean the same thing:

• Monday, November 16, 2026, starting that day: Microsoft said in a November 12, 2026, update that it will start removing the remaining eMudhra root certificates from the Microsoft Trusted Root Program, Windows, Microsoft Edge, WebView2, and related services. Once those changes reach a device or service, certificates that chain to those roots will no longer be trusted by default. This applies to existing certificates, not only newly issued ones.
• Monday, November 16, 2026, at 11:59:59 PM UTC (5:59 PM Central Time): Google said in a November 4, 2026, update that Chrome 153 and later will not trust TLS certificates that chain to emSign Root CA - G1 if the earliest Signed Certificate Timestamp (SCT) is after that time. Certificates whose earliest SCT is on or before that time remain trusted in Chrome under that change. Mozilla has set the same cutoff of November 16, 2026, 11:59:59 UTC, as a TLS "distrust-after" date for emSign Root CA - G1, so certificates issued after that cutoff are rejected; certificates issued on or before it may continue to validate. In short, Chrome and Firefox are stopping new G1 certificates after that time, not immediately dropping every existing G1 certificate.
• Monday, November 30, 2026: In a November 5, 2026, update, eMudhra said Apple has indicated it will remove G1, and that this means all certificates issued under the G1 hierarchy, whenever they were issued, will cease to be trusted on Apple platforms. As of November 13, 2026, we have not found a separate Apple page that states the November 30 date in those terms. Apple's support article, published November 9, 2026, confirms the automatic block of the compromised intermediates and of emSign ECC Root CA - G3, and lists emSign Root CA - G1 among roots that certain macOS updates remove from the certificate file used by some command-line tools.

eMudhra said on November 5, 2026, that it had already migrated emSign TLS certificates to other providers in all regions except the United States, where a large group of customers was still being moved, and that it expected the remaining customers to be transitioned before Apple's date. In an earlier October 28 update, it said roughly 30,800 certificates had been issued under the affected G3 hierarchies to a client ecosystem in the United States, and that those customers had been given an alternate path through the G1 RSA root. Anyone still on a G1 certificate should not assume it will keep working past the dates above.

What to do now

1. Check the certificate on your website. In your browser, open the site, click the padlock next to the address, and view the certificate. Look at the issuer and the certificate chain for the names eMudhra or emSign, including emSign ECC Root CA - G3 and emSign Root CA - G1. If you are not sure how to read the chain, ask the company that hosts your site, the vendor that sold you the certificate, or your IT provider.
2. Check more than the public website. Email servers, customer portals, APIs, VPN appliances, and other services that use HTTPS can have their own certificates. If those certificates chain to an eMudhra or emSign root, they need the same replacement.
3. If the certificate chains to emSign ECC Root CA - G3, replace it immediately. Chrome, Firefox, and Apple have already stopped trusting that root. Visitors may already see a security warning.
4. If the certificate chains to emSign Root CA - G1 or another remaining eMudhra root, replace it before November 16. That is when Microsoft says remaining eMudhra roots will start to be removed from Windows and Edge. Even if an existing G1 certificate would still be accepted in Chrome or Firefox after November 16, it may stop working for Windows, Edge, and, according to eMudhra, for Apple platforms on November 30. Get a certificate from a different trusted provider and install it; do not wait for the current one to expire.
5. If eMudhra or your certificate vendor has already offered a free replacement, follow through and install it. eMudhra has said it will replace affected certificates at no cost through partners. A replacement still has to be installed on the server or device for visitors to receive it.
6. Keep Windows and browser updates turned on. Microsoft and the browser vendors have been delivering these trust-list changes through ordinary updates. Microsoft also advises organizations with disconnected Windows devices to make sure those devices receive the updated trust lists.
7. Do not click through a certificate warning. If a site you use starts showing a certificate error, stop and contact the site operator. Do not bypass the warning to get work done.

As of November 13, 2026, the practical step for most small businesses is a certificate inventory this week, and a replacement installed before November 16 if an eMudhra or emSign chain is still in use.