CVE-2026-42256
net-imap: Denial of service via high iteration count for `SCRAM-*` authentication
- State
- Published
- Severity
- 6.0 Medium
- Published
- May 9, 2026
- Updated
- May 11, 2026
- Reserved
- Apr 26, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.0 Medium | 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 | GitHub_M |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
net-imapruby |
|
References
- https://github.com/ruby/net-imap/security/advisories/GHSA-87pf-fpwv-p7m7
- https://github.com/ruby/net-imap/commit/158d0b505074397cdb5ceb58935e42dd2bcfa612
- https://github.com/ruby/net-imap/commit/808001bc45c06f7297a7e96d341279e041a7f7f4
- https://github.com/ruby/net-imap/commit/99f59eab6064955a23debd95410263ad144df758
- https://github.com/ruby/net-imap/releases/tag/v0.4.24
- https://github.com/ruby/net-imap/releases/tag/v0.5.14
- https://github.com/ruby/net-imap/releases/tag/v0.6.4
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