DescriptionAn issue was discovered in Ruby through 2.6.7, 2.7.x through 2.7.3, and 3.x through 3.0.1. Net::IMAP does not raise an exception when StartTLS fails with an an unknown response, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a "StartTLS stripping attack."
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
Debian Bugs990815

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
jruby (PTS)stretch1.7.26-1+deb9u1vulnerable
stretch (security)1.7.26-1+deb9u3vulnerable
sid, buster9.1.17.0-3vulnerable
ruby2.3 (PTS)stretch2.3.3-1+deb9u8vulnerable
stretch (security)2.3.3-1+deb9u9vulnerable
ruby2.5 (PTS)buster2.5.5-3+deb10u3vulnerable
buster (security)2.5.5-3+deb10u2vulnerable
ruby2.7 (PTS)bullseye, sid2.7.4-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs


[buster] - jruby <no-dsa> (Minor issue)
[stretch] - jruby <no-dsa> (Minor issue) (2.7)

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