CVE-2026-42246

EUVD-2026-28924
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
UNKNOWN
---
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Common Weakness Enumeration
References
https://github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54cc0fd9618
https://github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdbb3eb8485e
https://github.com/ruby/net-imap/commit/97e2488fb5401a1783bddd959dde007d9fbce42c
https://github.com/ruby/net-imap/commit/f79d35bf5833f186e81044c57c843eda30c873da
https://github.com/ruby/net-imap/releases/tag/v0.3.10
https://github.com/ruby/net-imap/releases/tag/v0.4.24
https://github.com/ruby/net-imap/releases/tag/v0.5.14
https://github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcp