Email

Rspamd 4.1.0 dropped on June 5 — a major release tagged “recommended upgrade for all users” by the development team. There’s enough in it that’s immediately relevant to anyone running a mail server to warrant reading the changelog before blindly upgrading. The security fixes This release addresses several memory-safety issues that can be triggered by crafted incoming mail. S/MIME DoS via recursive PKCS7: A deeply nested application/pkcs7-mime message re-entered the parser without incrementing the nesting counter. In practice this means a malicious sender could craft a message that exhausts your rspamd worker’s stack. The fix gates S/MIME re-entry against the existing max_nested limit. ...

Google and Yahoo dropped their email authentication hammer in February 2024. Microsoft watched that unfold, nodded slowly, and then did the same thing on May 5, 2025. If your domain hasn’t sorted out SPF, DKIM, and DMARC by now, a chunk of your outbound mail is already being rejected — silently, with no bounce to show for it. What Microsoft Actually Requires For anyone sending 5,000 or more messages per day to Microsoft consumer addresses (@outlook.com, @hotmail.com, @live.com), the requirements are: ...

On May 4, 2026, Wietse Venema released Postfix 3.11.2, 3.10.9, 3.9.10, and 3.8.16. If you run a mail server, this is the update you actually want to read — not because the CVSS score is alarming (it isn’t), but because one of the bugs patched in this release has been sitting in the codebase since 2005. The CVE Worth Knowing About CVE-2026-43964 is an off-by-one error in how Postfix handles enhanced status codes. If an SMTP access table, policy server, DNSBL response, or milter returns a bare status code — something like 5.7.2 without any text following it — the daemon reads past the end of the allocated buffer. The result is a process crash. ...

In late March, the Dovecot team published advisory OXDC-ADV-2026-0001 — a bundle of eight CVEs covering everything from pre-authentication path traversal to SQL injection to multiple denial-of-service vectors. If Dovecot is the IMAP daemon on your mail server (it almost certainly is), this deserves your attention. Here is a breakdown of what matters, in roughly descending order of alarm. The Serious Ones CVE-2026-24031 — SQL injection auth bypass (CVSS 7.7, HIGH) ...