{"id":"CVE-2026-107575","revision":"3a020104b49940d99749d20d7cc929b2","records":[{"revision":"3a020104b49940d99749d20d7cc929b2","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-107575","aliases":[],"title":"Inefficient Algorithmic Complexity in hMailServer","description":"Inefficient algorithmic complexity in the SPF macro expansion of Progressive Robot hMailServer 6.3.4 and 6.3.5 allows a remote unauthenticated attacker to consume worker-thread time by publishing a crafted SPF record. RFC 7208 section 7.1 requires a name too long to look up to lose whole labels from the left; the server did this by removing one label at a time and copying the rest of the name each time, so the work grew with the square of the expansion. An attacker who publishes an SPF record for a domain they control, with a mechanism whose domain-spec expands through macros to a name far longer than 253 characters, makes the SPF check of a message from that domain take several seconds. The expansion is bounded by SPF's own per-term and per-macro limits, so the loss of availability is partial.","state":0,"publishedAt":"2026-10-08T11:46:46.082+00:00","modifiedAt":"2026-10-08T14:17:04.989+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\": \"6.3.4\",\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:N/S:U/C:N/I:N/A:L","score":5.3,"severity":"MEDIUM"}],"references":["https://gitlab.com/hmailserver/hmailserver/-/work_items/74","https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-107575","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-107575","identifiers":["CVE-2026-107575"]},"retained":false,"historicalAffected":[]}],"coverage":[]}