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CVE-2026-42246

net-imap vulnerable to STARTTLS stripping via invalid response timing

Published: May 9, 2026Updated: Aug 5, 2026 Sources: CVE List NVDCWE-392
7.4HIGH
NVD MITRE
EPSS Score
0.3%
Top 76.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-392CWE-393CWE-636CWE-754CWE-841CWE-325

Affected Products

ruby
oss-project·JP
net-imapLibrary
OSS Libraries / rubygems
ruby-lang
oss-projectaka rexml, ruby
net\LibraryLibrary
OSS Libraries / rubygems

Exploitability

Official Patch Available
Workaround Available
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References

https://github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcp
github.com
https://github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54cc0fd9618
github.com
https://github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdbb3eb8485e
github.com
and 28 more references View all →

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