{"schema":"threatline.record/2","record":{"id":"CVE-2026-107572","aliases":[],"summary":"Inefficient Regular Expression Complexity in hMailServer","details":"Inefficient complexity in the Sieve filter evaluation of Progressive Robot hMailServer 6.2.24 through 6.3.5 allows an authenticated account holder to make the mail services unavailable with their own filter. A ':matches' pattern was matched by a backtracking descent whose time grew with the matched value's length raised to the number of wildcards, so a pattern such as '*a*a*a*b' over 800 characters took 44 seconds; and 'deleteheader' erased the fields it removed one at a time, so removing many fields of one name over a message's header cost O(N^2) (80,000 fields took 18.8 seconds). Sieve filters run on the small, shared delivery thread pool, so an account holder whose active script does this, fed a few messages they can send themselves, empties the pool and stops delivery for the whole server. The script is the account holder's own and cannot be set for another user.","categories":["Unclassified"],"product":"hMailServer","vendor":"Progressive Robot Ltd","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-107572","source_modified_at":"2026-10-08T17:35:21.719Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"hMailServer","vendor":"Progressive Robot Ltd","versions":[{"version":"6.2.24","status":"affected","lessThan":"6.3.6","versionType":"semver"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-107572","source_modified_at":"2026-10-08T17:35:21.719Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"hMailServer","ecosystem":null},"version":"6.3.6","basis":"first unaffected version stated in the CVE record"}],"cvss":6.5,"severity":"Medium","kev":{"listed":false},"epss":{"probability":0.00307,"percentile":0.22289,"score_date":"2026-10-23"},"published_at":"2026-10-08T11:46:41.080Z","modified_at":"2026-10-08T17:35:21.719Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-107572","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-08T17:35:21.719Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-107572","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://gitlab.com/hmailserver/hmailserver/-/work_items/75"},{"source":"CVE List","url":"https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"partial","assessed_at":"2026-10-08T17:35:04.470485Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-08T17:35:21.719Z","content_hash":"f1c264b60ea66a11d2675e38b0c620a95fb9e5286746367519e124a0c704d4b6"}}