CVE-2026-42256

medium

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

https://github.com/ruby/net-imap/security/advisories/GHSA-87pf-fpwv-p7m7

https://github.com/ruby/net-imap/releases/tag/v0.6.4

https://github.com/ruby/net-imap/releases/tag/v0.5.14

https://github.com/ruby/net-imap/releases/tag/v0.4.24

https://github.com/ruby/net-imap/commit/99f59eab6064955a23debd95410263ad144df758

https://github.com/ruby/net-imap/commit/808001bc45c06f7297a7e96d341279e041a7f7f4

https://github.com/ruby/net-imap/commit/158d0b505074397cdb5ceb58935e42dd2bcfa612

Details

Source: Mitre, NVD

Published: 2026-05-09

Updated: 2026-05-18

Risk Information

CVSS v2

Base Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

Severity: High

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Severity: Medium

CVSS v4

Base Score: 6

Vector: 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

Severity: Medium

EPSS

EPSS: 0.0005