I had the same problem as Erik C.J. Laan, the original poster.
My CA certificate is imported into the "Authorities" section of Icedove's certificates, but I have imported no other certificates. This setup has been working for a long time in Debian and it works on Thunderbird in Windows.
Following Daniel Kahn Gillmor's (dkg) suggestion in #15, on my mail server, I "re-generate[d] the same self-signed certificate with the same key using SHA1 as the message-signing digest." That allowed the new version of libnss3 to work for me.
I agree with dkg that "this sounds to me like a bug in the logic of the upgraded version of NSS." It needs to be fixed.
Thanks, dkg! Regards, Phil -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org