CVE-2025-3523

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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": "When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL header, only the last link is shown when hovering over any attachment. Although the correct link is used on click, the misleading hover text could trick users into downloading content from untrusted sources. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2."}, {"lang": "es", "value": "Cuando un correo electr\u00f3nico contiene varios archivos adjuntos con enlaces externos mediante el encabezado X-Mozilla-External-Attachment-URL, solo se muestra el \u00faltimo enlace al pasar el cursor sobre cualquier archivo adjunto. Aunque se usa el enlace correcto al hacer clic, el texto enga\u00f1oso al pasar el cursor podr\u00eda inducir a los usuarios a descargar contenido de fuentes no confiables. 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-2025-3523", "lastModified": "2026-06-17T09:20:06.470", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 6.4, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L", "version": "3.1"}, "exploitabilityScore": 1.6, "impactScore": 4.7, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-3523", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2025-04-15T17:45:32.075828Z", "version": "2.0.3"}}]}, "published": "2025-04-15T15:16:09.957", "references": [{"source": "security@mozilla.org", "tags": ["Permissions Required"], "url": "https://bugzilla.mozilla.org/show_bug.cgi?id=1958385"}, {"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-451"}], "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: User Interface (UI) Misrepresentation of attachment URL", "id": "2359786", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2359786"}, "csaw": false, "cvss3": {"cvss3_base_score": "6.4", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L", "status": "verified"}, "cwe": "CWE-451", "details": ["When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL header, only the last link is shown when hovering over any attachment. Although the correct link is used on click, the misleading hover text could trick users into downloading content from untrusted sources. This vulnerability affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2."], "name": "CVE-2025-3523", "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": "2025-04-15T15:06:14Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-3523\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-3523\nhttps://bugzilla.mozilla.org/show_bug.cgi?id=1958385\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": "Low"}

{"analysis": {"en": {"generated_at": "2026-04-20T17:16:30.835036+00:00", "value": {"mitigation_remediation": ["Upgrade Thunderbird to version 137.0.2 or later, or to version 128.9.2 or later if using that release line", "Enable attachment verification or sandboxing features within Thunderbird or the operating system to reduce the impact of malicious attachments", "Use an email security gateway to filter or neutralize the X\u2011Mozilla\u2011External\u2011Attachment\u2011URL header in inbound messages"], "summary": {"action": "Apply Patch", "impact": "UI Misrepresentation Leading to Possible Social Engineering"}, "threat_synthesis": {"affected_systems": "The vulnerability affects the Mozilla Thunderbird email client in all versions prior to Thunderbird\u202f128.9.2 and Thunderbird\u202f137.0.2. No other vendor or product is listed as affected in this report. The specific affected releases are therefore all Thunderbird builds older than the two patched versions, irrespective of platform. No additional products or operating system components are indicated.", "description_and_impact": "An email containing multiple attachments can include external URLs via the X-Mozilla-External-Attachment-URL header. Thunderbird displays only the last of those URLs as the hover text for every attachment, while the correct URL is used when the attachment is clicked. This visual inconsistency can mislead users into thinking that a safe link is being displayed, potentially causing them to download content from untrusted or malicious sources. The flaw is classified as CWE\u2011451 \u2013 Untrustworthy Implementation of a Safety\u2011Relevant Function. The impact is primarily social engineering; a user can be tricked into interacting with a harmful attachment, which may compromise confidentiality, integrity, or availability of the user\u2019s machine or data.", "risk_and_exploitability": "The CVSS score of 6.4 reflects moderate severity. The EPSS score of less than 1% indicates a very low probability of exploitation at the time of analysis, and the issue is not currently listed in CISA\u2019s KEV catalog. Attackers would need to craft an email that targets Thunderbird users and relies on the hover misrepresentation to influence user behavior. Therefore, the risk is primarily driven by user interaction and social engineering rather than automated exploitation."}}}}, "created": "2026-04-20T17:30:12.660846+00:00", "updated": "2026-04-20T17:30:12.660856+00:00", "vendors": []}