{"id":"UBUNTU-CVE-2026-42256","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.","modified":"2026-07-06T16:02:59.197422848Z","published":"2026-05-09T20:16:00Z","related":["USN-8478-1"],"upstream":["CVE-2026-42256"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-42256"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-42256"},{"type":"REPORT","url":"https://github.com/ruby/net-imap/commit/158d0b505074397cdb5ceb58935e42dd2bcfa612"},{"type":"REPORT","url":"https://github.com/ruby/net-imap/commit/808001bc45c06f7297a7e96d341279e041a7f7f4"},{"type":"REPORT","url":"https://github.com/ruby/net-imap/commit/99f59eab6064955a23debd95410263ad144df758"},{"type":"REPORT","url":"https://github.com/ruby/net-imap/releases/tag/v0.4.24"},{"type":"REPORT","url":"https://github.com/ruby/net-imap/releases/tag/v0.5.14"},{"type":"REPORT","url":"https://github.com/ruby/net-imap/releases/tag/v0.6.4"},{"type":"REPORT","url":"https://github.com/ruby/net-imap/security/advisories/GHSA-87pf-fpwv-p7m7"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8478-1"}],"affected":[{"package":{"name":"jruby","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/jruby?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.4.8.0+ds-2ubuntu1","9.4.8.0+ds-3ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"jruby","binary_version":"9.4.8.0+ds-3ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42256.json"}},{"package":{"name":"ruby3.3","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/ruby3.3?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.3.7-1ubuntu2","3.3.8-2ubuntu1","3.3.8-2ubuntu2","3.3.8-2ubuntu2.1"],"ecosystem_specific":{"binaries":[{"binary_name":"libruby3.3","binary_version":"3.3.8-2ubuntu2.1"},{"binary_name":"ruby3.3","binary_version":"3.3.8-2ubuntu2.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42256.json"}},{"package":{"name":"ruby3.3","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/ruby3.3?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.3.8-2ubuntu3.1"}]}],"versions":["3.3.8-2ubuntu2","3.3.8-2ubuntu3"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"3.3.8-2ubuntu3.1","binary_name":"libruby3.3"},{"binary_name":"ruby3.3","binary_version":"3.3.8-2ubuntu3.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-42256.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}