CVE-2026-107574

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-107574", "assignerOrgId": "ceab7361-8a18-47b1-92ba-4d7d25f6715a", "state": "PUBLISHED", "assignerShortName": "GitLab", "dateReserved": "2026-10-08T10:51:35.642Z", "datePublished": "2026-10-08T11:46:26.206Z", "dateUpdated": "2026-10-08T14:15:58.279Z"}, "containers": {"cna": {"title": "Inefficient Algorithmic Complexity in hMailServer", "descriptions": [{"lang": "en", "value": "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."}], "affected": [{"vendor": "Progressive Robot Ltd", "product": "hMailServer", "repo": "https://gitlab.com/hmailserver/hmailserver", "versions": [{"version": "6.2.28", "status": "affected", "lessThan": "6.3.6", "versionType": "semver"}], "defaultStatus": "unaffected"}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "CWE-407: Inefficient Algorithmic Complexity", "cweId": "CWE-407", "type": "CWE"}]}], "references": [{"url": "https://gitlab.com/hmailserver/hmailserver/-/work_items/76"}, {"url": "https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH"}}], "solutions": [{"lang": "en", "value": "Upgrade to hMailServer 6.3.6, which keeps the member names seen in a hash set, so a JSON object is read in one pass. Until then, where domain reports are on, move the report mailbox off a hosted domain; restart the service to end a busy thread."}], "credits": [{"lang": "en", "value": "Found in the hMailServer project's own security review (Progressive Robot Ltd)", "type": "finder"}], "providerMetadata": {"orgId": "ceab7361-8a18-47b1-92ba-4d7d25f6715a", "shortName": "GitLab", "dateUpdated": "2026-10-08T11:46:26.206Z"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-10-08T14:15:32.913666Z", "id": "CVE-2026-107574", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-08T14:15:58.279Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-107574", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-08T14:15:32.913666Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-08T14:15:54.649Z"}}], "cna": {"title": "Inefficient Algorithmic Complexity in hMailServer", "credits": [{"lang": "en", "type": "finder", "value": "Found in the hMailServer project's own security review (Progressive Robot Ltd)"}], "metrics": [{"format": "CVSS", "cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"repo": "https://gitlab.com/hmailserver/hmailserver", "vendor": "Progressive Robot Ltd", "product": "hMailServer", "versions": [{"status": "affected", "version": "6.2.28", "lessThan": "6.3.6", "versionType": "semver"}], "defaultStatus": "unaffected"}], "solutions": [{"lang": "en", "value": "Upgrade to hMailServer 6.3.6, which keeps the member names seen in a hash set, so a JSON object is read in one pass. Until then, where domain reports are on, move the report mailbox off a hosted domain; restart the service to end a busy thread."}], "references": [{"url": "https://gitlab.com/hmailserver/hmailserver/-/work_items/76"}, {"url": "https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"}], "descriptions": [{"lang": "en", "value": "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."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-407", "description": "CWE-407: Inefficient Algorithmic Complexity"}]}], "providerMetadata": {"orgId": "ceab7361-8a18-47b1-92ba-4d7d25f6715a", "shortName": "GitLab", "dateUpdated": "2026-10-08T11:46:26.206Z"}}}, "cveMetadata": {"cveId": "CVE-2026-107574", "state": "PUBLISHED", "dateUpdated": "2026-10-08T14:15:58.279Z", "dateReserved": "2026-10-08T10:51:35.642Z", "assignerOrgId": "ceab7361-8a18-47b1-92ba-4d7d25f6715a", "datePublished": "2026-10-08T11:46:26.206Z", "assignerShortName": "GitLab"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "hMailServer", "repo": "https://gitlab.com/hmailserver/hmailserver", "vendor": "Progressive Robot Ltd", "versions": [{"lessThan": "6.3.6", "status": "affected", "version": "6.2.28", "versionType": "semver"}]}], "source": "cve@gitlab.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-107574", "lastModified": "2026-10-08T21:02:43.860", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "cve@gitlab.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-107574", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-08T14:15:32.913666Z", "version": "2.0.3"}}]}, "published": "2026-10-08T12:17:15.177", "references": [{"source": "cve@gitlab.com", "url": "https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"}, {"source": "cve@gitlab.com", "url": "https://gitlab.com/hmailserver/hmailserver/-/work_items/76"}], "sourceIdentifier": "cve@gitlab.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-407"}], "source": "cve@gitlab.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.2.28,6.3.6)"}}], "enrichment": {"confidence": 94.0, "confidence_source": "matching", "scores": [{"score": 94.0, "source": "matching"}]}, "original": {"product": "hMailServer", "source": "cna", "vendor": "Progressive Robot Ltd"}, "product": "hmailserver", "vendor": "progressive_robot"}], "created": "2026-10-08T13:30:18.036072+00:00", "updated": "2026-10-09T07:15:09.074129+00:00", "vendors": ["progressive_robot", "progressive_robot$PRODUCT$hmailserver"]}