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.
Affected products
ruby-lang: net\
References10
- github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcp MitigationVendor Advisory
- github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54… Patch
- github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdb… Patch
- github.com/ruby/net-imap/commit/97e2488fb5401a1783bddd959dde007… Patch
- github.com/ruby/net-imap/commit/f79d35bf5833f186e81044c57c843ed… Patch
- github.com/ruby/net-imap/releases/tag/v0.3.10 Release Notes
- github.com/ruby/net-imap/releases/tag/v0.4.24 Release Notes
- github.com/ruby/net-imap/releases/tag/v0.5.14 Release Notes
- access.redhat.com/errata/RHSA-2026:33462
- access.redhat.com/errata/RHSA-2026:33512
Metrics
- CVSS 3.1
-
7.4
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - CVSS 4.0
-
7.6
HIGH
Score source: CNA
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 25 · as of 14 November 2026
- CWE
- CWE-392CWE-393CWE-636CWE-754CWE-841CWE-325
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.