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CVE-2026-16396
Privilege escalation in WebExtensions
High8.8EPSS 0.24%
- Published
- Updated
- Reserved
- Assigned by
- mozilla
Description
Privilege escalation in WebExtensions. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
Timeline
ID reserved
By mozilla
- 1 day later
· 1 day later
Published
- 3 days later
· 3 days 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 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.24% · top 85% of all CVEs (8 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Weakness
Affected products
- unaffected 140.13 – ≤ 140.*
- unaffected 153 – ≤ *
- unaffected 140.13 – ≤ 140.*
- unaffected 153 – ≤ *
References (5)
- https://bugzilla.mozilla.org/show_bug.cgi?id=2047240 (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2026-68/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2026-70/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2026-71/ (opens in a new tab)
- https://www.mozilla.org/security/advisories/mfsa2026-72/ (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)
- 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-2026-16396)Record last updated .