Exim Security Release 4.100.1

Exim released security update 4.100.1 addressing vulnerabilities in the widely used open-source mail transfer agent; details remain sparse.

Solar Designer posted an oss-security notice pointing to an Exim-announce message from Bernard Quatermass dated September 18, 2026, announcing Exim Security Release 4.100.1. The public post contains no CVE identifiers, description of the fixed flaws, or exploitation details, linking instead to the official Exim mailing list announcement. Exim is a widely deployed mail transfer agent with a history of critical vulnerabilities, so administrators should apply the update promptly.

• Exim published security release 4.100.1 on September 18, 2026
• Announced via Exim-announce and relayed on oss-security
• No CVE ids, flaw details, or exploitation information in the notice
• Exim is a widely used MTA, so admins should patch promptly