CVE-2025-3522

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-3522", "assignerOrgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe", "state": "PUBLISHED", "assignerShortName": "mozilla", "dateReserved": "2025-04-11T15:23:30.875Z", "datePublished": "2025-04-15T15:06:13.599Z", "dateUpdated": "2026-04-13T14:28:27.731Z"}, "containers": {"cna": {"affected": [{"product": "Thunderbird", "vendor": "Mozilla", "versions": [{"status": "unaffected", "version": "128.9.2", "lessThanOrEqual": "128.*", "versionType": "rpm"}, {"status": "unaffected", "version": "137.0.2", "lessThanOrEqual": "*", "versionType": "rpm"}]}], "descriptions": [{"lang": "en", "value": "Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally. When an email is opened, Thunderbird accesses the specified URL to determine file size, and navigates to it when the user clicks the attachment. Because the URL is not validated or sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially leading to hashed Windows credential leakage and opening the door to more serious security issues. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.", "supportingMedia": [{"type": "text/html", "base64": false, "value": "Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally. When an email is opened, Thunderbird accesses the specified URL to determine file size, and navigates to it when the user clicks the attachment. Because the URL is not validated or sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially leading to hashed Windows credential leakage and opening the door to more serious security issues. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2."}]}], "title": "Leak of hashed Window credentials via crafted attachment URL", "references": [{"url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1955372"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2025-26/"}, {"url": "https://www.mozilla.org/security/advisories/mfsa2025-27/"}], "credits": [{"lang": "en", "value": "Dario Wei\u00dfer"}], "providerMetadata": {"orgId": "f16b083a-5664-49f3-a51e-8d479e5ed7fe", "shortName": "mozilla", "dateUpdated": "2026-04-13T14:28:27.731Z"}}, "adp": [{"problemTypes": [{"descriptions": [{"type": "CWE", "cweId": "CWE-601", "lang": "en", "description": "CWE-601 URL Redirection to Untrusted Site ('Open Redirect')"}]}], "metrics": [{"cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L", "integrityImpact": "LOW", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}}, {"other": {"type": "ssvc", "content": {"timestamp": "2025-04-15T18:49:37.244746Z", "id": "CVE-2025-3522", "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": "2025-04-15T19:05:13.896Z"}}]}}

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{"affected": [{"affectedData": [{"product": "Thunderbird", "vendor": "Mozilla", "versions": [{"lessThanOrEqual": "128.*", "status": "unaffected", "version": "128.9.2", "versionType": "rpm"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "137.0.2", "versionType": "rpm"}]}], "source": "security@mozilla.org"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*", "matchCriteriaId": "D11A3908-71D7-4967-8029-0D4DD57F384C", "versionEndExcluding": "128.9.2", "vulnerable": true}, {"criteria": "cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*", "matchCriteriaId": "971D9339-D135-4B63-A4DA-E333080DA5E6", "versionEndExcluding": "137.0.2", "versionStartIncluding": "129.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally. When an email is opened, Thunderbird accesses the specified URL to determine file size, and navigates to it when the user clicks the attachment. Because the URL is not validated or sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially leading to hashed Windows credential leakage and opening the door to more serious security issues. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2."}, {"lang": "es", "value": "Thunderbird procesa el encabezado X-Mozilla-External-Attachment-URL para gestionar los archivos adjuntos alojados externamente. Al abrir un correo electr\u00f3nico, Thunderbird accede a la URL especificada para determinar el tama\u00f1o del archivo y la accede cuando el usuario hace clic en el archivo adjunto. Dado que la URL no est\u00e1 validada ni depurada, puede hacer referencia a recursos internos como enlaces a chrome:// o a recursos compartidos SMB file://, lo que podr\u00eda provocar una fuga de credenciales de Windows con hash y dar lugar a problemas de seguridad m\u00e1s graves. Esta vulnerabilidad afecta a Thunderbird (versi\u00f3n anterior a la 137.0.2) y Thunderbird (versi\u00f3n anterior a la 128.9.2)."}], "id": "CVE-2025-3522", "lastModified": "2026-06-17T09:20:06.333", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.4, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-3522", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2025-04-15T18:49:37.244746Z", "version": "2.0.3"}}]}, "published": "2025-04-15T15:16:09.877", "references": [{"source": "security@mozilla.org", "tags": ["Permissions Required"], "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1955372"}, {"source": "security@mozilla.org", "tags": ["Vendor Advisory"], "url": "https://www.mozilla.org/security/advisories/mfsa2025-26/"}, {"source": "security@mozilla.org", "tags": ["Vendor Advisory"], "url": "https://www.mozilla.org/security/advisories/mfsa2025-27/"}], "sourceIdentifier": "security@mozilla.org", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-601"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{"affected_release": [{"advisory": "RHSA-2025:7507", "cpe": "cpe:/o:redhat:enterprise_linux:10.0", "package": "thunderbird-0:128.10.0-1.el10_0", "product_name": "Red Hat Enterprise Linux 10", "release_date": "2025-05-13T00:00:00Z"}, {"advisory": "RHSA-2025:4649", "cpe": "cpe:/a:redhat:enterprise_linux:8", "package": "thunderbird-0:128.9.2-1.el8_10", "product_name": "Red Hat Enterprise Linux 8", "release_date": "2025-05-07T00:00:00Z"}, {"advisory": "RHSA-2025:4389", "cpe": "cpe:/a:redhat:rhel_aus:8.2", "package": "thunderbird-0:128.9.2-1.el8_2", "product_name": "Red Hat Enterprise Linux 8.2 Advanced Update Support", "release_date": "2025-04-30T00:00:00Z"}, {"advisory": "RHSA-2025:4654", "cpe": "cpe:/a:redhat:rhel_aus:8.4", "package": "thunderbird-0:128.9.2-1.el8_4", "product_name": "Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support", "release_date": "2025-05-07T00:00:00Z"}, {"advisory": "RHSA-2025:4654", "cpe": "cpe:/a:redhat:rhel_tus:8.4", "package": "thunderbird-0:128.9.2-1.el8_4", "product_name": "Red Hat Enterprise Linux 8.4 Telecommunications Update Service", "release_date": "2025-05-07T00:00:00Z"}, {"advisory": "RHSA-2025:4654", "cpe": "cpe:/a:redhat:rhel_e4s:8.4", "package": "thunderbird-0:128.9.2-1.el8_4", "product_name": "Red Hat Enterprise Linux 8.4 Update Services for SAP Solutions", "release_date": "2025-05-07T00:00:00Z"}, {"advisory": "RHSA-2025:4665", "cpe": "cpe:/a:redhat:rhel_aus:8.6", "package": "thunderbird-0:128.9.2-1.el8_6", "product_name": "Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support", "release_date": "2025-05-07T00:00:00Z"}, {"advisory": "RHSA-2025:4665", "cpe": "cpe:/a:redhat:rhel_tus:8.6", "package": "thunderbird-0:128.9.2-1.el8_6", "product_name": "Red Hat Enterprise Linux 8.6 Telecommunications Update Service", "release_date": "2025-05-07T00:00:00Z"}, {"advisory": "RHSA-2025:4665", "cpe": "cpe:/a:redhat:rhel_e4s:8.6", "package": "thunderbird-0:128.9.2-1.el8_6", "product_name": "Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions", "release_date": "2025-05-07T00:00:00Z"}, {"advisory": "RHSA-2025:4617", "cpe": "cpe:/a:redhat:rhel_eus:8.8", "package": "thunderbird-0:128.9.2-1.el8_8", "product_name": "Red Hat Enterprise Linux 8.8 Extended Update Support", "release_date": "2025-05-07T00:00:00Z"}, {"advisory": "RHSA-2025:4229", "cpe": "cpe:/a:redhat:enterprise_linux:9", "package": "thunderbird-0:128.9.2-1.el9_5", "product_name": "Red Hat Enterprise Linux 9", "release_date": "2025-04-28T00:00:00Z"}, {"advisory": "RHSA-2025:7435", "cpe": "cpe:/a:redhat:enterprise_linux:9", "package": "thunderbird-0:128.10.0-1.el9_6", "product_name": "Red Hat Enterprise Linux 9", "release_date": "2025-05-13T00:00:00Z"}, {"advisory": "RHSA-2025:4514", "cpe": "cpe:/a:redhat:rhel_e4s:9.0", "package": "thunderbird-0:128.9.2-1.el9_0", "product_name": "Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions", "release_date": "2025-05-06T00:00:00Z"}, {"advisory": "RHSA-2025:4513", "cpe": "cpe:/a:redhat:rhel_eus:9.2", "package": "thunderbird-0:128.9.2-1.el9_2", "product_name": "Red Hat Enterprise Linux 9.2 Extended Update Support", "release_date": "2025-05-06T00:00:00Z"}, {"advisory": "RHSA-2025:4512", "cpe": "cpe:/a:redhat:rhel_eus:9.4", "package": "thunderbird-0:128.9.2-1.el9_4", "product_name": "Red Hat Enterprise Linux 9.4 Extended Update Support", "release_date": "2025-05-06T00:00:00Z"}], "bugzilla": {"description": "thunderbird: Leak of hashed Window credentials via crafted attachment URL", "id": "2359793", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2359793"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.4", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N", "status": "verified"}, "cwe": "CWE-1220", "details": ["Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally. When an email is opened, Thunderbird accesses the specified URL to determine file size, and navigates to it when the user clicks the attachment. Because the URL is not validated or sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially leading to hashed Windows credential leakage and opening the door to more serious security issues. This vulnerability affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2."], "name": "CVE-2025-3522", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "thunderbird-flatpak-container", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "thunderbird", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "thunderbird-flatpak-container", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2025-04-15T15:06:13Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-3522\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-3522\nhttps://bugzilla.mozilla.org/show_bug.cgi?id=1955372\nhttps://www.mozilla.org/security/advisories/mfsa2025-26/\nhttps://www.mozilla.org/security/advisories/mfsa2025-27/"], "statement": "Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.", "threat_severity": "Important"}

{"analysis": {"en": {"generated_at": "2026-04-20T20:35:11.988549+00:00", "value": {"mitigation_remediation": ["Update Thunderbird to 137.0.2 or a later patch series that includes the fix; apply all available security updates for the client.", "If updating is not immediately possible, configure the client or email gateway to ignore or block the X-Mozilla-External-Attachment-URL header so that external attachment URLs are not processed.", "Apply email filtering rules to reject or quarantine any message that contains the X-Mozilla-External-Attachment-URL header or references external resources, reducing the risk of credential leakage."], "summary": {"action": "Patch Immediately", "impact": "Information Disclosure of Hashed Windows Credentials"}, "threat_synthesis": {"affected_systems": "Mozilla Thunderbird email client versions prior to 137.0.2 and 128.9.2. Any installation of those earlier releases that processes the X-Mozilla-External-Attachment-URL header is potentially vulnerable. The issue is not specific to a particular operating system but the credential leakage impact applies to Windows-based Thunderbird clients.", "description_and_impact": "Thunderbird uses the X-Mozilla-External-Attachment-URL header to obtain attachments that can be hosted elsewhere. When a message is opened, the client connects to the URL to determine file size and later downloads the attachment when the user clicks it. Because the URL is not validated or sanitized, an attacker can supply a reference to internal resources such as chrome:// or SMB share file:// links. In Windows environments, this leads to the leakage of hashed credentials, which could enable further attacks. The weakness falls under CWE-1220 (Data Leakage) and CWE-601 (Open Redirect).", "risk_and_exploitability": "The CVSS score of 6.3 indicates a medium severity vulnerability, while the EPSS score of <1% suggests that exploitation attempts are currently rare. The vulnerability is not listed in CISA\u2019s KEV catalog. An attacker can exploit this flaw by sending a crafted email containing the vulnerable header; the victim must open the message for the client to access the URL and leak credentials. Because the flaw requires user interaction and is limited to the Thunderbird client, the overall risk is moderate, but it can be stepping stone to more serious exploits if the attacker gains additional footholds."}}}}, "created": "2026-04-20T20:45:16.931807+00:00", "updated": "2026-04-20T20:45:16.931827+00:00", "vendors": []}