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CVE-2026-46428
9.1 CRITICAL
- CVSS version (CVSS): 4.0
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): Low (L)
- Attack Requirement (AT): Present (P)
- Privileges Required (PR): None (N)
- User Interaction (UI): None (N)
- Vulnerable System Impact Confidentiality (VC): High (H)
- Vulnerable System Impact Integrity (VI): High (H)
- Vulnerable System Impact Availability (VA): None (N)
- Subsequent System Impact Confidentiality (SC): Low (L)
- Subsequent System Impact Integrity (SI): Low (L)
- Subsequent System Impact Availability (SA): None (N)
- Modified Attack Vector (MAV): Network (N)
- Modified Attack Complexity (MAC): Low (L)
- Modified Attack Requirement (MAT): Present (P)
- Modified Privileges Required (MPR): None (N)
- Modified User Interaction (MUI): None (N)
- Modified Vulnerable System Impact Confidentiality (MVC): High (H)
- Modified Vulnerable System Impact Integrity (MVI): High (H)
- Modified Vulnerable System Impact Availability (MVA): None (N)
- Modified Subsequent System Impact Confidentiality (MSC): Low (L)
- Modified Subsequent System Impact Integrity (MSI): Low (L)
- Modified Subsequent System Impact Availability (MSA): Negligible (N)
- Safety (S): Not Defined (X)
- Automatable (AU): Not Defined (X)
- Recovery (R): Not Defined (X)
- Value Density (V): Not Defined (X)
- Vulnerability Response Effort (RE): Not Defined (X)
- Provider Urgency (U): Not Defined (X)
- Confidentiality Req. (CR): Not Defined (X)
- Integrity Req. (IR): Not Defined (X)
- Availability Req. (AR): Not Defined (X)
- Exploit Maturity (E): Not Defined (X)
Activity log
- Created suggestion
lettre has TLS hostname verification disabled when using Boring TLS backend
lettre is a a mailer library for Rust. Starting in version 0.10.1 and prior to version 0.11.22, an inverted-boolean bug in lettre's `boring-tls` integration silently disables TLS hostname verification for callers using the default (strict) configuration. An on-path attacker presenting any chain-valid certificate for any domain can intercept SMTP submission, including PLAIN/LOGIN credentials and message contents, against any lettre user built with the `boring-tls` feature. Other TLS backends (`native-tls`, `rustls`) are unaffected. Version 0.11.22 patches the issue.
References
-
https://github.com/lettre/lettre/security/advisories/GHSA-4pj9-g833-qx53 x_refsource_CONFIRM
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https://github.com/lettre/lettre/releases/tag/v0.11.22 x_refsource_MISC
-
https://rustsec.org/advisories/RUSTSEC-2026-0141.html x_refsource_MISC
Affected products
lettre
- ==>= 0.10.1, < 0.11.22
Matching in nixpkgs
pkgs.kdePackages.klettres
Learn The Alphabet
pkgs.typstPackages.formalettre
None
pkgs.typstPackages.formalettre_0_1_0
None
pkgs.typstPackages.formalettre_0_1_1
None
pkgs.typstPackages.formalettre_0_1_2
None
pkgs.typstPackages.formalettre_0_1_3
None
pkgs.typstPackages.formalettre_0_2_0
None
pkgs.typstPackages.formalettre_0_3_0
None
pkgs.typstPackages.formalettre_0_3_1
None
Package maintainers
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@K900 Ilya K. <me@0upti.me>
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@LunNova Luna Nova <nixpkgs-maintainer@lunnova.dev>
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@NickCao Nick Cao <nickcao@nichi.co>
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@FRidh Frederik Rietdijk <fridh@fridh.nl>
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@SuperSandro2000 Sandro Jäckel <sandro.jaeckel@gmail.com>
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@nyanloutre Paul Trehiou <paul@nyanlout.re>
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@peterhoeg Peter Hoeg <peter@hoeg.com>
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@bkchr Bastian Köcher <nixos@kchr.de>
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@ilya-fedin Ilya Fedin <fedin-ilja2010@ya.ru>
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@mjm Matt Moriarity <matt@mattmoriarity.com>