{"id":"CVE-2026-42256","aliases":["GHSA-87pf-fpwv-p7m7"],"url":"https://o3.security/vulnerability/CVE-2026-42256","summary":"net-imap: Denial of service via high iteration count for `SCRAM-*` authentication","details":"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.","published":"2026-05-09T19:38:33.106Z","modified":"2026-09-14T12:11:42.360749461Z","cvss":null,"epss":{"score":0.00299,"percentile":0.22079,"asOf":"2026-09-02"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"RubyGems","name":"net-imap","fixedVersion":"0.6.4"},{"ecosystem":"RubyGems","name":"net-imap","fixedVersion":"0.5.14"},{"ecosystem":"RubyGems","name":"net-imap","fixedVersion":"0.4.24"}],"fix":{"url":"https://github.com/ruby/net-imap/commit/158d0b505074397cdb5ceb58935e42dd2bcfa612","label":"ruby/net-imap@158d0b5"},"references":[{"type":"WEB","url":"https://github.com/ruby/net-imap/releases/tag/v0.4.24"},{"type":"WEB","url":"https://github.com/ruby/net-imap/releases/tag/v0.5.14"},{"type":"WEB","url":"https://github.com/ruby/net-imap/releases/tag/v0.6.4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42256.json"},{"type":"ADVISORY","url":"https://github.com/ruby/net-imap/security/advisories/GHSA-87pf-fpwv-p7m7"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-42256"},{"type":"FIX","url":"https://github.com/ruby/net-imap/commit/158d0b505074397cdb5ceb58935e42dd2bcfa612"},{"type":"FIX","url":"https://github.com/ruby/net-imap/commit/808001bc45c06f7297a7e96d341279e041a7f7f4"},{"type":"FIX","url":"https://github.com/ruby/net-imap/commit/99f59eab6064955a23debd95410263ad144df758"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-14T12:11:42.360749461Z"}}