{"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"}}]}}