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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-42256

31
FAUCET Score

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.

First published: May 9, 2026Last modified: May 11, 2026

Impacted Technologies

VendorProductVersion(s)CPE
>= 0.4.0, < 0.4.24CPE matchmatch criteria
cpe:2.3:a:ruby-lang:net\:\:imap:*:*:*:*:*:ruby:*:*
>= 0.5.0, < 0.5.14CPE matchmatch criteria
cpe:2.3:a:ruby-lang:net\:\:imap:*:*:*:*:*:ruby:*:*
>= 0.6.0, < 0.6.4CPE matchmatch criteria
cpe:2.3:a:ruby-lang:net\:\:imap:*:*:*:*:*:ruby:*:*

CVSS Data

CVSS version used by this source: 4.0

6.0MEDIUM

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/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

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
PASSIVE
VS Confidentiality
NONE
VS Integrity
NONE
VS Availability
HIGH
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.30%
Probability of exploitation in next 30 days
EPSS Percentile
22.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0030 is in the 22nd percentile among its peer group of 26,221 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

github_advisorypatch availablevia nvd_reference
View patch
rubygemspatch availablevia ghsa
Product: net-imapFixed in: 0.6.4
rubygemspatch availablevia ghsa
Product: net-imapFixed in: 0.5.14
rubygemspatch availablevia ghsa
Product: net-imapFixed in: 0.4.24

Vendor Advisories (2)

microsoft2026-May/CVE-2026-42256Moderate

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

May 7, 2026
rubygemsGHSA-87pf-fpwv-p7m7medium

net-imap vulnerable to denial of service via high iteration count for `SCRAM-*` authentication

May 4, 2026

References

github.com / ruby/net-imap/commit/158d0b505074397cdb5ceb58935e42dd2bcfa612
Patch
github.com / ruby/net-imap/commit/808001bc45c06f7297a7e96d341279e041a7f7f4
Patch
github.com / ruby/net-imap/commit/99f59eab6064955a23debd95410263ad144df758
Patch
github.com / ruby/net-imap/releases/tag/v0.4.24
Release Notes
github.com / ruby/net-imap/releases/tag/v0.5.14
Release Notes
github.com / ruby/net-imap/releases/tag/v0.6.4
Release Notes
github.com / ruby/net-imap/security/advisories/GHSA-87pf-fpwv-p7m7
MitigationVendor Advisory