CVE-2026-42246
Published:May 09, 2026
Updated:May 16, 2026
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.
Affected Packages
https://github.com/ruby/net-imap.git (GITHUB):
Affected version(s) >=v0.6.0 <v0.6.4Fix Suggestion:
Update to version v0.6.4https://github.com/ruby/net-imap.git (GITHUB):
Affected version(s) >=v0.1.0 <v0.3.10Fix Suggestion:
Update to version v0.3.10https://github.com/ruby/net-imap.git (GITHUB):
Affected version(s) >=v0.5.0 <v0.5.14Fix Suggestion:
Update to version v0.5.14https://github.com/ruby/net-imap.git (GITHUB):
Affected version(s) >=v0.4.0 <v0.4.24Fix Suggestion:
Update to version v0.4.24net-imap (RUBY):
Affected version(s) >=0.5.0 <0.5.14Fix Suggestion:
Update to version 0.5.14net-imap (RUBY):
Affected version(s) >=0.1.0 <0.3.10Fix Suggestion:
Update to version 0.3.10net-imap (RUBY):
Affected version(s) >=0.4.0 <0.4.24Fix Suggestion:
Update to version 0.4.24net-imap (RUBY):
Affected version(s) >=0.6.0 <0.6.4Fix Suggestion:
Update to version 0.6.4net-imap (RUBY):
Affected version(s) >=0.1.0 <0.3.10Fix Suggestion:
Update to version 0.3.10Related Resources (14)
Do you need more information?
Contact UsCVSS v4
Base Score:
7.6
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
8.1
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
EPSS
Base Score:
0.07