--- a/security/manager/ssl/security-prefs.js
+++ b/security/manager/ssl/security-prefs.js
@@ -130,9 +130,9 @@ pref("security.ssl.errorReporting.automa
 // https://tools.ietf.org/html/rfc7469#section-4.1
 pref("security.cert_pinning.max_max_age_seconds", 5184000);
 
 // security.pki.distrust_ca_policy controls what root program distrust policies
 // are enforced at this time:
 // 0: No distrust policies enforced
 // 1: Symantec root distrust policy enforced
 // See https://wiki.mozilla.org/CA/Upcoming_Distrust_Actions for more details.
-pref("security.pki.distrust_ca_policy", 0);
+pref("security.pki.distrust_ca_policy", 1);