{"id":"CVE-2026-107572","revision":"33cb65b8644348bab3b5f04f3fa1157c","records":[{"revision":"33cb65b8644348bab3b5f04f3fa1157c","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-107572","aliases":[],"title":"Inefficient Regular Expression Complexity in hMailServer","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.","state":0,"publishedAt":"2026-10-08T11:46:41.08+00:00","modifiedAt":"2026-10-08T17:35:21.719+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\": \"6.2.24\",\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:L/UI:N/S:U/C:N/I:N/A:H","score":6.5,"severity":"MEDIUM"}],"references":["https://gitlab.com/hmailserver/hmailserver/-/work_items/75","https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-107572","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-107572","identifiers":["CVE-2026-107572"]},"retained":false,"historicalAffected":[]}],"coverage":[]}