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CVE-2020-6813
When protecting CSS blocks with the nonce feature of Content Security Policy, the @import statement in the CSS block could allow an…
Medium5.3EPSS 1.2%
- Published
- Updated
- Reserved
- Assigned by
- mozilla
Description
When protecting CSS blocks with the nonce feature of Content Security Policy, the @import statement in the CSS block could allow an attacker to inject arbitrary styles, bypassing the intent of the Content Security Policy. This vulnerability affects Firefox < 74.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 1.2% · top 31% of all CVEs (7 Nov 2026)
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Weakness
- @import statements in CSS could bypass the Content Security Policy nonce feature
Affected products
References (2)
- https://www.mozilla.org/security/advisories/mfsa2020-08/ (opens in a new tab)x_refsource_MISCx_transferred
- https://bugzilla.mozilla.org/show_bug.cgi?id=1605814 (opens in a new tab)x_refsource_MISCx_transferred
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://trackcve.app/cve/CVE-2020-6813)Record last updated .