{"id":"CVE-2026-107575","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-107575","generatedAt":"2026-10-28T01:02:28.875Z","title":"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.","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.","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":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},"cwe":["CWE-407"],"affected":[],"epss":{"score":0.00387,"percentile":0.32551,"date":"2026-10-26","history":[{"date":"2026-10-09","score":0.00387,"percentile":0.3072}]},"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 (0.39%). 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":"5.3","severity":"MEDIUM","publishedAt":"2026-10-08T12:17:15.333Z"},"summary":"New CVE, medium severity (CVSS 5.3)."}],"references":[{"url":"https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6","source":"cve@gitlab.com"},{"url":"https://gitlab.com/hmailserver/hmailserver/-/work_items/74","source":"cve@gitlab.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-107575","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."}