{"schema":"threatline.record/2","record":{"id":"CVE-2026-107574","aliases":[],"summary":"Inefficient Algorithmic Complexity in hMailServer","details":"Inefficient algorithmic complexity in the JSON reader of Progressive Robot hMailServer allows a remote unauthenticated attacker to make the mail services unavailable. Reading a JSON object kept the first of each duplicated member name by searching the members already read, so an object of N distinct member names cost O(N^2): 1 MB took 8.9 seconds and 4 MB took 300 seconds against the affected code. A remote attacker reaches the reader without an account by mailing a crafted TLS-RPT report (up to 16 MB after decompression) to a hosted domain's published report mailbox, which is read on a delivery thread; a few such reports hold every delivery thread (ten by default), so the server delivers no mail, local or outbound, for over an hour per report. A signed-in account reaches the same 16 MB body through the webmail's own REST routes, holding the REST API's own worker threads. Where no report mailbox is configured, the unauthenticated REST sign-in routes that read a JSON body are capped at 64 KB and are not affected.","categories":["Unclassified"],"product":"hMailServer","vendor":"Progressive Robot Ltd","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-107574","source_modified_at":"2026-10-08T14:15:58.279Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"hMailServer","vendor":"Progressive Robot Ltd","versions":[{"version":"6.2.28","status":"affected","lessThan":"6.3.6","versionType":"semver"}],"defaultStatus":"unaffected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-107574","source_modified_at":"2026-10-08T14:15:58.279Z","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":7.5,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00428,"percentile":0.35999,"score_date":"2026-10-23"},"published_at":"2026-10-08T11:46:26.206Z","modified_at":"2026-10-08T14:15:58.279Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-107574","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-08T14:15:58.279Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-107574","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/76"},{"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":"yes","technical_impact":"partial","assessed_at":"2026-10-08T14:15:32.913666Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-08T14:15:58.279Z","content_hash":"300af95712d8999a17f400b93b7d54f09f3a2c6335a7a48612a497fd81e1b63c"}}