CVE-2026-42256

MEDIUM

net-imap: Denial of service via high iteration count for `SCRAM-*` authentication

Title source: cna
STIX 2.1

Description

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. From versions 0.4.0 to before 0.4.24, 0.5.0 to before 0.5.14, and 0.6.0 to before 0.6.4, when authenticating a connection with SCRAM-SHA1 or SCRAM-SHA256, a hostile server can perform a computational denial-of-service attack on the client process by sending a big iteration count value. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.

References (7)

Core 7
Core References
X_Refsource_Misc x_refsource_misc
https://github.com/ruby/net-imap/releases/tag/v0.4.24
X_Refsource_Misc x_refsource_misc
https://github.com/ruby/net-imap/releases/tag/v0.5.14
X_Refsource_Misc x_refsource_misc
https://github.com/ruby/net-imap/releases/tag/v0.6.4

Scores

CVSS v3 6.5
EPSS 0.0005
EPSS Percentile 14.3%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-1322 CWE-770
Status published
Products (7)
ruby/net-imap >= 0.4.0, < 0.4.24
ruby/net-imap >= 0.5.0, < 0.5.14
ruby/net-imap >= 0.6.0, < 0.6.4
ruby-lang/net\ 0.4.0 - 0.4.24
rubygems/net-imap 0.4.0 - 0.4.24RubyGems
rubygems/net-imap 0.5.0 - 0.5.14RubyGems
rubygems/net-imap 0.6.0 - 0.6.4RubyGems
Published May 09, 2026
Tracked Since May 10, 2026