> USN-9013-1: Fetchmail vulnerabilities

Christian Herdtweck discovered that Fetchmail incorrectly handled certain long log messages. A remote attacker could possibly use this issue to cause Fetchmail to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2021-36386) It was discovered that the Fetchmail SMTP client incorrectly handled certain status code messages. An attacker controlling a malicious server could possibly use this issue to cause Fetchmail to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2025-61962) Tristan Madani discovered that Fetchmail incorrectly handled certain NTLM authentication challenges. A remote attacker could possibly use this issue to cause Fetchmail to crash, resulting in a denial of service, or possibly execute arbitrary code. The default compiler options for affected releases should reduce the vulnerability to a denial of service. (CVE-2026-94184)