{"id":"CVE-2026-107572","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-107572","generatedAt":"2026-10-28T02:59:07.064Z","title":"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.","description":"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.","published":"2026-10-08T12:17:15.000Z","lastModified":"2026-10-08T21:02:44.000Z","status":"Deferred","sourceIdentifier":"cve@gitlab.com","cvss":{"version":"3.1","score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-1333"],"affected":[],"epss":{"score":0.00307,"percentile":0.23253,"date":"2026-10-26","history":[{"date":"2026-10-09","score":0.00307,"percentile":0.21563}]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.31%). Track it; it rarely justifies an emergency change on its own."},"changes":[{"kind":"new","label":"New CVE","at":"2026-10-08T12:17:15.000Z","detail":{"score":"6.5","severity":"MEDIUM","publishedAt":"2026-10-08T12:17:14.870Z"},"summary":"New CVE, medium severity (CVSS 6.5)."}],"references":[{"url":"https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6","source":"cve@gitlab.com"},{"url":"https://gitlab.com/hmailserver/hmailserver/-/work_items/75","source":"cve@gitlab.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-107572","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}