lettre has TLS hostname verification disabled when using Boring TLS backend
Critical vendor advisory
CVE-2026-46428
Summary
lettre has TLS hostname verification disabled when using Boring TLS backend
Why it matters
GitHub has published a reviewed security advisory for lettre. Prioritize it with other application dependency updates, especially because EPSS places it in the 9% percentile.
Operator check
Check whether lettre is present in application dependency manifests, lockfiles, or build images. Review the GitHub advisory and upgrade to a patched version where available. CVSS score: 9.1. EPSS probability: 0.2%; percentile: 9%.
Sources
PatchBrief uses public sources. It does not scan environments, verify exposure, or replace vendor guidance.