{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-107581",
        "assignerOrgId": "ceab7361-8a18-47b1-92ba-4d7d25f6715a",
        "state": "PUBLISHED",
        "assignerShortName": "GitLab",
        "dateReserved": "2026-10-08T10:52:10.640Z",
        "datePublished": "2026-10-08T11:47:16.084Z",
        "dateUpdated": "2026-10-08T14:19:53.760Z"
    },
    "containers": {
        "cna": {
            "title": "Inefficient Algorithmic Complexity in hMailServer",
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Progressive Robot hMailServer 6.0.0 through 6.3.5 processes several IMAP commands from a signed-in account in time quadratic in the command's length or in the number of elements it names, and can be made to hold memory out of proportion to a command. The FETCH data-item parser normalised a BODY[] section with a case-insensitive string replacement that copied the whole item per occurrence and split the item list by repeatedly copying the remainder of the command; the server's case-insensitive search compared a needle afresh at every position, so a long SEARCH TEXT key over a message cost the product of the two lengths; SEARCH message sets and the saved-result marker ($), SORT criteria, HEADER.FIELDS name lists and UID ranges were each read once per message rather than once per command; and a FETCH naming a message's sections very many times read and held every section in memory before sending any. An IMAP command may continue past one line through non-synchronizing literals, so one command can reach about eleven megabytes. The IMAP worker threads are a small pool shared with SMTP and POP3, so a signed-in user sending such commands can make the IMAP, SMTP and POP3 services stop responding (CWE-407) and can consume excessive memory (CWE-400)."
                }
            ],
            "affected": [
                {
                    "vendor": "Progressive Robot Ltd",
                    "product": "hMailServer",
                    "repo": "https://gitlab.com/hmailserver/hmailserver",
                    "versions": [
                        {
                            "version": "6.0.0",
                            "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/68"
                },
                {
                    "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:L/UI:N/S:U/C:N/I:N/A:H",
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "privilegesRequired": "LOW",
                        "userInteraction": "NONE",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "NONE",
                        "availabilityImpact": "HIGH",
                        "baseScore": 6.5,
                        "baseSeverity": "MEDIUM"
                    }
                }
            ],
            "solutions": [
                {
                    "lang": "en",
                    "value": "Upgrade to hMailServer 6.3.6, which parses the FETCH command and runs the server's case-insensitive string operations in a single pass, reads each SEARCH and UID set and HEADER.FIELDS list once per command, substitutes the saved-result marker once, and refuses a FETCH whose sections add up to many times the message before sending any. There is no configuration workaround; the commands require only a signed-in account. Restricting IMAP access to trusted accounts and networks reduces who can send them."
                }
            ],
            "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": "2026-10-08T11:47:16.084Z"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-10-08T14:18:56.518928Z",
                                "id": "CVE-2026-107581",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "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": "2026-10-08T14:19:53.760Z"
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    }
}