{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-107575",
        "assignerOrgId": "ceab7361-8a18-47b1-92ba-4d7d25f6715a",
        "state": "PUBLISHED",
        "assignerShortName": "GitLab",
        "dateReserved": "2026-10-08T10:51:40.639Z",
        "datePublished": "2026-10-08T11:46:46.082Z",
        "dateUpdated": "2026-10-08T14:17:04.989Z"
    },
    "containers": {
        "cna": {
            "title": "Inefficient Algorithmic Complexity in hMailServer",
            "descriptions": [
                {
                    "lang": "en",
                    "value": "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."
                }
            ],
            "affected": [
                {
                    "vendor": "Progressive Robot Ltd",
                    "product": "hMailServer",
                    "repo": "https://gitlab.com/hmailserver/hmailserver",
                    "versions": [
                        {
                            "version": "6.3.4",
                            "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/74"
                },
                {
                    "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:L",
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "NONE",
                        "availabilityImpact": "LOW",
                        "baseScore": 5.3,
                        "baseSeverity": "MEDIUM"
                    }
                }
            ],
            "solutions": [
                {
                    "lang": "en",
                    "value": "Upgrade to hMailServer 6.3.6, which finds where the name becomes short enough and cuts it once. Until then, turn SPF checking off, or accept the bounded delay."
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "Found in the hMailServer project's own security review (Progressive Robot Ltd)",
                    "type": "finder"
                }
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                "orgId": "ceab7361-8a18-47b1-92ba-4d7d25f6715a",
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                "dateUpdated": "2026-10-08T11:46:46.082Z"
            }
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            {
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                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-10-08T14:16:55.314371Z",
                                "id": "CVE-2026-107575",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "yes"
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                                        "Technical Impact": "partial"
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                                "role": "CISA Coordinator",
                                "version": "2.0.3"
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                "title": "CISA ADP Vulnrichment",
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}