HomeCVE Intelligence › CVE-2026-46428
CVSS 9.5 CRITICAL Security Vulnerability

CVE-2026-46428: lettre has TLS hostname verification disabled when using Boring TLS backend

Summary 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 certifi…

9.5CVSS Score
CRITICALSeverity
NOCISA KEV
0.2%EPSS Score
Security VulnerabilityImpact Type

📋 Vulnerability Details

CVE IDCVE-2026-46428
VendorMultiple Vendors
Affected ProductMultiple Products
Vulnerability TypeSecurity Vulnerability
CVSS Score9.5 (CRITICAL)
EPSS Score0.2% probability of exploitation in the next 30 days
Actively Exploited❌ No known exploitation
Patch StatusPending Vendor Disclosure
Reported ByCYBERDUDEBIVASH SENTINEL APEX Intelligence (via sentinel_apex)

🔬 Technical Analysis

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Summary

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, incl... [Full analysis available on Pro]

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