CVE-2026-42246: CWE-392: Missing Report of Error Condition in ruby net-imap
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.
AI Analysis
Technical Summary
The Ruby net-imap library implements IMAP client functionality. Versions before 0.3.10, 0.4.24, 0.5.14, and 0.6.4 contain a vulnerability (CWE-392) where the starttls method can falsely indicate a successful TLS handshake under man-in-the-middle conditions, failing to start TLS encryption. This can expose communications to interception. The vulnerability has been fixed in the stated versions.
Potential Impact
An attacker positioned as a man-in-the-middle can intercept and manipulate IMAP traffic by exploiting the failure to properly initiate TLS, potentially exposing sensitive email data. The vulnerability affects confidentiality and integrity of communications. There are no known exploits in the wild at this time.
Mitigation Recommendations
Upgrade the net-imap library to version 0.3.10, 0.4.24, 0.5.14, or 0.6.4 or later, where this vulnerability is patched. Patch status is confirmed by the version fixes listed. No additional mitigations are specified.
CVE-2026-42246: CWE-392: Missing Report of Error Condition in ruby net-imap
Description
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Ruby net-imap library implements IMAP client functionality. Versions before 0.3.10, 0.4.24, 0.5.14, and 0.6.4 contain a vulnerability (CWE-392) where the starttls method can falsely indicate a successful TLS handshake under man-in-the-middle conditions, failing to start TLS encryption. This can expose communications to interception. The vulnerability has been fixed in the stated versions.
Potential Impact
An attacker positioned as a man-in-the-middle can intercept and manipulate IMAP traffic by exploiting the failure to properly initiate TLS, potentially exposing sensitive email data. The vulnerability affects confidentiality and integrity of communications. There are no known exploits in the wild at this time.
Mitigation Recommendations
Upgrade the net-imap library to version 0.3.10, 0.4.24, 0.5.14, or 0.6.4 or later, where this vulnerability is patched. Patch status is confirmed by the version fixes listed. No additional mitigations are specified.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-25T05:37:12.118Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69ff93c0cbff5d86106e4582
Added to database: 5/9/2026, 8:06:24 PM
Last enriched: 5/9/2026, 8:21:19 PM
Last updated: 5/10/2026, 7:37:55 AM
Views: 13
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.