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Lettre

3 CVEs product

Monthly

CVE-2026-46428 Jul 20, 15:37 Cargo CRITICAL PATCH GHSA Act Now

TLS hostname verification bypass in the lettre Rust mailer library (0.10.1 through 0.11.21) exposes users of the boring-tls feature to man-in-the-middle attacks; an inverted boolean caused the default strict configuration to silently disable hostname checking. An on-path attacker holding any chain-valid certificate for any domain can transparently intercept SMTP submission, harvesting PLAIN/LOGIN credentials and full message contents. There is no public exploit identified at time of analysis, but the one-line root cause is visible in the public fix commit, making the flaw trivially understandable; native-tls and rustls backends are not affected.

Information Disclosure Lettre
NVD GitHub
CVSS 4.0
9.1
EPSS
0.2%
CVE-2021-38189 Aug 08, 06:15 Cargo CRITICAL POC PATCH Act Now

An issue was discovered in the lettre crate before 0.9.6 for Rust. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Command Injection Lettre
NVD
CVSS 3.1
9.8
EPSS
1.5%
CVE-2020-28247 Nov 12, 18:15 Cargo MEDIUM PATCH This Month

The lettre library through 0.10.0-alpha for Rust allows arbitrary sendmail option injection via transport/sendmail/mod.rs. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

Code Injection Lettre
NVD GitHub
CVSS 3.1
5.3
EPSS
1.5%
EPSS 0% CVSS 9.1
CRITICAL PATCH Act Now

TLS hostname verification bypass in the lettre Rust mailer library (0.10.1 through 0.11.21) exposes users of the boring-tls feature to man-in-the-middle attacks; an inverted boolean caused the default strict configuration to silently disable hostname checking. An on-path attacker holding any chain-valid certificate for any domain can transparently intercept SMTP submission, harvesting PLAIN/LOGIN credentials and full message contents. There is no public exploit identified at time of analysis, but the one-line root cause is visible in the public fix commit, making the flaw trivially understandable; native-tls and rustls backends are not affected.

Information Disclosure Lettre
NVD GitHub
EPSS 1% CVSS 9.8
CRITICAL POC PATCH Act Now

An issue was discovered in the lettre crate before 0.9.6 for Rust. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Command Injection Lettre
NVD
EPSS 2% CVSS 5.3
MEDIUM PATCH This Month

The lettre library through 0.10.0-alpha for Rust allows arbitrary sendmail option injection via transport/sendmail/mod.rs. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

Code Injection Lettre
NVD GitHub

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