{"id":"CVE-2026-107580","revision":null,"records":[{"revision":"d238a27214e740328aad89591d7bffc2","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-107580","aliases":[],"title":"Inefficient Algorithmic Complexity in hMailServer","description":"Inefficient algorithmic complexity in the decoding of message header fields in Progressive Robot hMailServer 6.0.0 through 6.3.5 allows a remote unauthenticated attacker to make the IMAP, SMTP and POP3 services, or the webmail, unavailable by sending a message. The server unfolded a decoded header value by finding each line break from the end of the value and removing it, moving the rest of the value each time, so its work grew with the square of the number of line breaks, and an RFC 2047 encoded word may decode to any number of them. A received message whose Subject or other header field holds such a value keeps a worker thread busy for minutes or longer each time the value is read: when the recipient's IMAP client searches, sorts or threads the folder by a header, when the webmail lists the folder, and, where configured, when a rule tests a header, a spam tag is added to the Subject or an abuse report is read during delivery. The IMAP worker threads are shared with SMTP and POP3, so a few such messages stop those services responding. The server's reading of a message header from its file also searched everything read so far after each 4,000 bytes, costing seconds for a header of tens of megabytes.","state":0,"publishedAt":"2026-10-08T11:47:11.085+00:00","modifiedAt":"2026-10-08T14:20:26.21+00:00","affected":[{"ecosystem":"Vendor product","name":"hMailServer","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"Progressive Robot Ltd\",\n                    \"product\": \"hMailServer\",\n                    \"repo\": \"https://gitlab.com/hmailserver/hmailserver\",\n                    \"versions\": [\n                        {\n                            \"version\": \"6.0.0\",\n                            \"status\": \"affected\",\n                            \"lessThan\": \"6.3.6\",\n                            \"versionType\": \"semver\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","score":6.5,"severity":"MEDIUM"}],"references":["https://gitlab.com/hmailserver/hmailserver/-/work_items/69","https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-107580","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-107580","identifiers":["CVE-2026-107580"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-a5bcdf6ab6d94076983501bc0e56dd96","complete":false,"records":13754,"lastAttemptAt":"2026-11-11T08:39:48.5063796+00:00","lastSuccessAt":"2026-11-11T08:39:48.502+00:00","error":"16 identifier lookups failed; latest failures include HTTP 403. Other identifiers were checked independently.","lastVerifiedAt":"2026-11-11T08:39:48.502+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13770,"expectedIdentifiers":13808,"failedIdentifiers":16},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-11T08:27:47.0671487+00:00","complete":true,"records":1097,"lastAttemptAt":"2026-11-11T08:27:47.0671487+00:00","lastSuccessAt":"2026-11-11T08:27:47.3858436+00:00","error":null,"lastVerifiedAt":"2026-11-11T08:27:47.3858438+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-4463bca2214348638313ac7302b155ec","complete":true,"records":13748,"lastAttemptAt":"2026-11-11T08:27:47.8884887+00:00","lastSuccessAt":"2026-11-11T07:26:17.628+00:00","error":null,"lastVerifiedAt":"2026-11-11T07:26:17.628+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13808,"expectedIdentifiers":13808,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-3562b6c78fd1bd0f0b55daf66a0926ae24f65e462df7f6d928caad458fc696bf","complete":true,"records":9947,"lastAttemptAt":"2026-11-11T08:27:46.9180255+00:00","lastSuccessAt":"2026-11-11T04:27:43.6877707+00:00","error":null,"lastVerifiedAt":"2026-11-11T08:27:46.9180255+00:00","snapshotPublishedAt":"2026-11-11T03:32:46+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-456002455e0ab94bb92c95476d4e6d175c104cd594749982afd96c893728ecbc","complete":true,"records":2010,"lastAttemptAt":"2026-11-11T08:25:46.0590741+00:00","lastSuccessAt":"2026-11-11T02:36:58.1276999+00:00","error":null,"lastVerifiedAt":"2026-11-11T08:25:46.0590741+00:00","snapshotPublishedAt":"2026-11-11T01:17:51+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-0e3796c351bac632fda8fc3b3641da2bc6f0237cd79e78b1e59d17ce0aa22d32","complete":true,"records":3081,"lastAttemptAt":"2026-11-11T08:27:47.0269454+00:00","lastSuccessAt":"2026-11-10T20:24:10.5326555+00:00","error":null,"lastVerifiedAt":"2026-11-11T08:27:47.0269454+00:00","snapshotPublishedAt":"2026-11-10T20:03:04+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-085e065fc9050ae18408f7e722c39653aeb186872334d7b3ec1fcafb7ed43d25","complete":true,"records":231665,"lastAttemptAt":"2026-11-11T08:27:46.7420627+00:00","lastSuccessAt":"2026-11-11T08:27:45.2700102+00:00","error":null,"lastVerifiedAt":"2026-11-11T08:27:46.7420627+00:00","snapshotPublishedAt":"2026-11-11T07:32:59+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}