{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2025-3909",
        "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
        "state": "PUBLISHED",
        "assignerShortName": "mozilla",
        "dateReserved": "2025-04-23T17:44:42.650Z",
        "datePublished": "2025-05-14T16:56:43.630Z",
        "dateUpdated": "2026-04-13T14:27:53.020Z"
    },
    "containers": {
        "cna": {
            "affected": [
                {
                    "product": "Thunderbird",
                    "vendor": "Mozilla",
                    "versions": [
                        {
                            "status": "unaffected",
                            "version": "128.10.1",
                            "lessThanOrEqual": "128.*",
                            "versionType": "rpm"
                        },
                        {
                            "status": "unaffected",
                            "version": "138.0.1",
                            "lessThanOrEqual": "*",
                            "versionType": "rpm"
                        }
                    ]
                }
            ],
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context. By crafting a nested email attachment (message/rfc822) and setting its content type to application/pdf, Thunderbird may incorrectly render it as HTML when opened, allowing the embedded JavaScript to run without requiring a file download. This behavior relies on Thunderbird auto-saving the attachment to /tmp and linking to it via the file:/// protocol, potentially enabling JavaScript execution as part of the HTML. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1.",
                    "supportingMedia": [
                        {
                            "type": "text/html",
                            "base64": false,
                            "value": "Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context. By crafting a nested email attachment (message/rfc822) and setting its content type to application/pdf, Thunderbird may incorrectly render it as HTML when opened, allowing the embedded JavaScript to run without requiring a file download. This behavior relies on Thunderbird auto-saving the attachment to /tmp and linking to it via the file:/// protocol, potentially enabling JavaScript execution as part of the HTML. This vulnerability was fixed in Thunderbird 128.10.1 and Thunderbird 138.0.1."
                        }
                    ]
                }
            ],
            "title": "JavaScript Execution via Spoofed PDF Attachment and file:/// Link",
            "references": [
                {
                    "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1958376"
                },
                {
                    "url": "https://www.mozilla.org/security/advisories/mfsa2025-34/"
                },
                {
                    "url": "https://www.mozilla.org/security/advisories/mfsa2025-35/"
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "Dario Weißer"
                }
            ],
            "providerMetadata": {
                "orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe",
                "shortName": "mozilla",
                "dateUpdated": "2026-04-13T14:27:53.020Z"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "cvssV3_1": {
                            "scope": "UNCHANGED",
                            "version": "3.1",
                            "baseScore": 8.1,
                            "attackVector": "NETWORK",
                            "baseSeverity": "HIGH",
                            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N",
                            "integrityImpact": "HIGH",
                            "userInteraction": "REQUIRED",
                            "attackComplexity": "LOW",
                            "availabilityImpact": "NONE",
                            "privilegesRequired": "NONE",
                            "confidentialityImpact": "HIGH"
                        }
                    },
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "id": "CVE-2025-3909",
                                "role": "CISA Coordinator",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "total"
                                    }
                                ],
                                "version": "2.0.3",
                                "timestamp": "2025-05-16T03:55:44.016748Z"
                            }
                        }
                    }
                ],
                "problemTypes": [
                    {
                        "descriptions": [
                            {
                                "lang": "en",
                                "type": "CWE",
                                "cweId": "CWE-356",
                                "description": "CWE-356 Product UI does not Warn User of Unsafe Actions"
                            }
                        ]
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-02-26T18:28:09.659Z"
                }
            },
            {
                "title": "CVE Program Container",
                "references": [
                    {
                        "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00022.html"
                    }
                ],
                "providerMetadata": {
                    "orgId": "af854a3a-2127-422b-91ae-364da2661108",
                    "shortName": "CVE",
                    "dateUpdated": "2025-11-03T19:58:39.208Z"
                }
            }
        ]
    }
}