{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-27824",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-02-24T02:32:39.799Z",
        "datePublished": "2026-02-27T19:46:07.612Z",
        "dateUpdated": "2026-03-02T12:54:32.182Z"
    },
    "containers": {
        "cna": {
            "title": "calibre has IP Ban Bypass via X-Forwarded-For Header Spoofing",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-307",
                            "lang": "en",
                            "description": "CWE-307: Improper Restriction of Excessive Authentication Attempts",
                            "type": "CWE"
                        }
                    ]
                },
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-346",
                            "lang": "en",
                            "description": "CWE-346: Origin Validation Error",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "NONE",
                        "baseScore": 5.3,
                        "baseSeverity": "MEDIUM",
                        "confidentialityImpact": "LOW",
                        "integrityImpact": "NONE",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/kovidgoyal/calibre/security/advisories/GHSA-vhxc-r7v8-2xrw",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/kovidgoyal/calibre/security/advisories/GHSA-vhxc-r7v8-2xrw"
                }
            ],
            "affected": [
                {
                    "vendor": "kovidgoyal",
                    "product": "calibre",
                    "versions": [
                        {
                            "version": "< 9.4.0",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-02-27T19:46:07.612Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "calibre is a cross-platform e-book manager for viewing, converting, editing, and cataloging e-books. Prior to version 9.4.0, the calibre Content Server's brute-force protection mechanism uses a ban key derived from both `remote_addr` and the `X-Forwarded-For` header. Since the `X-Forwarded-For` header is read directly from the HTTP request without any validation or trusted-proxy configuration, an attacker can bypass IP-based bans by simply changing or adding this header, rendering the brute-force protection completely ineffective. This is particularly dangerous for calibre servers exposed to the internet, where brute-force protection is the primary defense against credential stuffing and password guessing attacks. Version 9.4.0 contains a fix for the issue."
                }
            ],
            "source": {
                "advisory": "GHSA-vhxc-r7v8-2xrw",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-03-02T12:54:19.314863Z",
                                "id": "CVE-2026-27824",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "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": "2026-03-02T12:54:32.182Z"
                }
            }
        ]
    }
}