CVE-2025-6430Content-Disposition header ignored when a file is included in an embed or object tag
- 6.1MediumCVSS base score
- 0.27%Exploitation in 30 daysEPSS · top 81% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
When a file download is specified via the `Content-Disposition` header, that directive would be ignored if the file was included via a `<embed>` or `<object>` tag, potentially making a website vulnerable to a cross-site scripting attack. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
Timeline
ID reserved
By mozilla
- 4 days later
· 4 days later
Published
- 10 months later
· 10 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Medium6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.27% · top 81% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.1.
Affected products
- unaffected 128.12 – ≤ 128.*
- unaffected 140 – ≤ *
- unaffected 128.12 – ≤ 128.*
- unaffected 140 – ≤ *
References
References7
- https://bugzilla.mozilla.org/show_bug.cgi?id=1971140 (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-51/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-53/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-54/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2025-55/ (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2025/07/msg00002.html (opens in a new tab)
- https://lists.debian.org/debian-lts-announce/2025/06/msg00029.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2025-21377 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2025-6430)Record last updated .