High (7.4). EPSS 2.9% chance of exploitation in the next 30 days.
An 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."
Severity
CVSS 3.1
7.4 high
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS
2.9% chance of exploitation in the next 30 days; higher than 86% of CVEs (scores of 2026-10-31)