medium6.5
CVE-2026-42256
net-imap vulnerable to denial of service via high iteration count for `SCRAM-*` authentication
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rubygems | net-imap | >= 0.6.0, <= 0.6.3 | 0.6.4 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Ruby-Lang | Net\ | from 0.4.0 before 0.4.24 from 0.5.0 before 0.5.14 from 0.6.0 before 0.6.4 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-87pf-fpwv-p7m7
- 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
- https://www.rfc-editor.org/rfc/rfc7804.html#page-15
- https://nvd.nist.gov/vuln/detail/CVE-2026-42256
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/net-imap/CVE-2026-42256.yml