{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-107585",
        "assignerOrgId": "ceab7361-8a18-47b1-92ba-4d7d25f6715a",
        "state": "PUBLISHED",
        "assignerShortName": "GitLab",
        "dateReserved": "2026-10-08T10:52:30.638Z",
        "datePublished": "2026-10-08T15:11:19.477Z",
        "dateUpdated": "2026-10-08T15:11:19.477Z"
    },
    "containers": {
        "cna": {
            "title": "Allocation of Resources Without Limits or Throttling in hMailServer",
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Uncontrolled eviction in the pending sign-in tables of the REST API in Progressive Robot hMailServer 6.3.4 and 6.3.5 allows a remote unauthenticated attacker to make other users' OpenID Connect, SAML and passkey sign-ins fail. The routes that start a single sign-on and hand out a passkey sign-in challenge are reached without authentication and stored pending state in bounded tables that dropped their oldest entry when full, whoever had started it. An attacker who starts sign-ins a few times a second (about a hundred a second for passkeys) pushes every other user's pending sign-in out of the table before that user's browser returns, denying single sign-on and passkey sign-in for as long as the requests continue."
                }
            ],
            "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-770: Allocation of Resources Without Limits or Throttling",
                            "cweId": "CWE-770",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://gitlab.com/hmailserver/hmailserver/-/work_items/63"
                },
                {
                    "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, in which a pending OpenID Connect, SAML or passkey sign-in is no longer held on the server at all but carried by the browser in a cookie sealed with AES-256-GCM under a key held only in memory and good once, so there is no table a flood of unauthenticated starts can fill. Until then: limit the rate of /portal/oidc/start, /portal/saml/start and /api/v1/passkeys/challenge per client at a reverse proxy, and keep password sign-in available for administrators."
                }
            ],
            "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": "2026-10-08T15:11:19.477Z"
            }
        }
    }
}