Adding %00 and a fake extension to a jar: URL changed the interpretation of the contents (Mozilla Firefox)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.45 % · percentile 39 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- mozilla
- NVD status
- Modified
Description
jar: URLs retrieve local file content packaged in a ZIP archive. The null and everything after it was ignored when retrieving the content from the archive, but the fake extension after the null was used to determine the type of content. This could have been used to hide code in a web extension disguised as something else like an image. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.
Weaknesses (CWE)
- CWE-158 — Improper Neutralization of Null Byte or NUL Character
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1940027
- https://www.mozilla.org/security/advisories/mfsa2025-14/
- https://www.mozilla.org/security/advisories/mfsa2025-16/
- https://www.mozilla.org/security/advisories/mfsa2025-17/
- https://www.mozilla.org/security/advisories/mfsa2025-18/
- https://lists.debian.org/debian-lts-announce/2025/03/msg00006.html
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L | CISA-ADP |
| CVSS 3.1 | HIGH 7.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L | NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
European references
- ENISA EUVD · EUVD-2025-7441
- GCVE · GCVE-0-2025-1936
CERT-FR advisories
- CERTFR-2025-AVI-0756 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2025-AVI-0176 — Multiples vulnérabilités dans les produits Mozilla · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*< 128.8.0cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*< 136.0cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*< 128.8.0cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*≥ 129.0 < 136.0
Affected products
| Product | Versions |
|---|---|
| Mozilla · Firefox | unaffected 128.8 ≤ 128.* ; unaffected 136 ≤ * |
| Mozilla · Thunderbird | unaffected 128.8 ≤ 128.* ; unaffected 136 ≤ * |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |