CVE-2026-42246
net-imap vulnerable to STARTTLS stripping via invalid response timing
7.4
HIGH
CVSS 3.1
EPSS 0.02%
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.
How to fix CVE-2026-42246
To remediate CVE-2026-42246, upgrade the affected package to a fixed version below.
- —no fix listed
- —no fix listed
- —no fix listed
- —upgrade to 0.6.4 or later
Is CVE-2026-42246 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (4)
- from 0
- from 0
- from 0
- >= 0.6.0, < 0.6.4
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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 |
| osv | CVSS 3.1 | HIGH7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |