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.
History

Sat, 09 May 2026 20:00:00 +0000

Type Values Removed Values Added
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.
Title net-imap vulnerable to STARTTLS stripping via invalid response timing
Weaknesses CWE-392
CWE-393
CWE-636
CWE-754
CWE-841
References
Metrics cvssV4_0

{'score': 7.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-09T19:33:17.880Z

Reserved: 2026-04-25T05:37:12.118Z

Link: CVE-2026-42246

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-09T20:16:28.163

Modified: 2026-05-09T20:16:28.163

Link: CVE-2026-42246

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-09T21:30:42Z