Improper input validation in Mozilla Firefox
Priority LOW 27CWE-20Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.0 · NVD. Fix status from CNA.
Summary
WebExtensions could use popups and panels in the extension UI to load an "about:" privileged URL, violating security checks that disallow this behavior. This vulnerability affects Firefox < 56.
Why it matters now
EPSS 0.01234 69th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed Firefox (Mozilla): 56
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Firefox (Mozilla) Fixed in 56
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
Mozilla Firefox 56
9 records Highest priority Priority MEDIUM 2 MEDIUM, 7 LOW
Other records, highest priority first
- TI-2017-05438 Incorrect permission assignment in Mozilla FirefoxPriority MEDIUM 46
- TI-2017-05428 Memory corruption in Mozilla FirefoxPriority MEDIUM 46
- TI-2017-05430 Out-of-bounds read in Mozilla FirefoxPriority LOW 39
Timeline
- 2026-10-02 Threatist record created from CVE-2017-7816
- 2026-10-03 Alias added: GHSA-q9h8-ghr2-6995
References
More Mozilla Firefox vulnerabilities
- TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
- TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
- TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
- TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
- TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
- TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
Sources
- CVE-2017-7816 · CVE Program
- CVE-2017-7816 · NVD
- FIRST EPSS
- GHSA-q9h8-ghr2-6995 · GitHub Advisory Database · CC BY 4.0
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