CA/Additional Trust Changes

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The Mozilla Root Program's official repository of the roots it trusts is certdata.txt. Some information about the level of trust in each root is included in that file - for example, whether it's trusted for server SSL, S/MIME or both. However, not all restrictions recommended by Mozilla on the roots can be or are encoded in certdata.txt. Some are implemented in our security library, "NSS", or in Firefox and Thunderbird (so-called "PSM").

Sometimes, other companies and organizations decide to use Mozilla's root store in their products. As the CA FAQ notes, Mozilla does not promise to take into account the needs of other users of its root store when making decisions. However, for the benefit of such users and on a best-efforts basis, this page documents the additional trust settings that Mozilla recommends.

Extended Validation (EV)

The status of whether a root is approved to issue EV certificates or not is stored in PSM rather than certdata.txt.


While not technically a modification to the root store as we don't use it for un-trusting roots, Mozilla's OneCRL system is used for communicating information about the revocation of intermediate certificates (and high-profile misissued end-entity certificates) to Firefox clients. Reports are provided about revoked intermediate certificates on the CA/Intermediate Certificates wiki page.

Distrust After

For some root certificates Mozilla has set 'Distrust for TLS After Date' or 'Distrust for S/MIME After Date'. For certificates chaining up to those root certificates, Mozilla does not trust end-entity certificates that have a Valid-From date later than the specified distrust-after date. Certificates with a Valid-From date earlier than the distrust-after date will continue to be trusted until the certificate's natural expiration or until the certificate is revoked.

These root certificates may be identified via the 'Included CA Certificates' reports on the CA/Included Certificates wiki page. Within those reports look for dates in the 'Distrust for TLS After Date' and 'Distrust for S/MIME After Date' columns.

Kamu SM

The Turkish Government CA is name-constrained to *.tr. (code change)


In accordance with the consensus proposal that was adopted in 2017, Mozilla began to distrust Symantec (including GeoTrust, RapidSSL, and Thawte) certificates issued before 1-June 2016 starting in Firefox 60, and plans to distrust Symantec certificates regardless of the date of issuance starting in Firefox 64, unless they are issued by whitelisted subordinate CAs that have the following SHA-256 Subject Public Key hashes (subjectPublicKeyInfo):




Note: In some instances, multiple subordinate CAs contain the same public key, necessitating whitelisting by subjectPublicKeyInfo. Refer to (Bug 1409257) for more information.

The Firefox preference "security.pki.distrust_ca_policy" may be set to '2' to enable distrust (regardless of issuance date) and '0' to override these changes. Mozilla plans to remove this preference in Firefox 65.

In a future Firefox release, we expect to remove the whitelist, and remove the ‘websites’ trust bit from all Symantec roots. The timing of these changes, and any changes to the ‘email’ trust bit (S/MIME) have not yet been determined.

Update December 2020:
The following 10 root certificates were removed via bug 1670769 from NSS 3.60 and Firefox 85.

  1. GeoTrust Global CA
  2. GeoTrust Primary Certification Authority
  3. GeoTrust Primary Certification Authority - G3
  4. thawte Primary Root CA
  5. thawte Primary Root CA - G3
  6. VeriSign Class 3 Public Primary Certification Authority - G4
  7. VeriSign Class 3 Public Primary Certification Authority - G5
  8. thawte Primary Root CA - G2
  9. GeoTrust Universal CA
  10. GeoTrust Universal CA 2

Update June 2020:
There is a new Distrust-After capability available in certdata.txt, which is enforced as of Firefox 78 (Bug #1615438), and will be enforced in Thunderbird at a later date. The following Bugzilla bugs were filed to use this capability. This update was described in the forum.

  • Symantec root certs - Set CKA_NSS_SERVER_DISTRUST_AFTER
    • Implemented in NSS 3.53, Firefox 78.
    • Setting CKA_NSS_SERVER_DISTRUST_AFTER to the specified dates distrusts TLS certs that have “Valid From” newer than the specified date. TLS certificates issued prior to this date will continue to be trusted until the certificate’s natural expiration or until we disable the trust bit or remove the root.
  • Symantec root certs - Set CKA_NSS_EMAIL_DISTRUST_AFTER
    • Setting CKA_NSS_EMAIL_DISTRUST_AFTER to the specified dates distrusts S/MIME certs that have “Valid From” newer than the specified date. S/MIME certificates issued prior to this date will continue to be trusted until the certificate’s natural expiration or until we disable the trust bit or remove the root.