CVE-2017-7839
Control characters prepended before "javascript:" URLs pasted in the addressbar can cause the leading characters to be ignored and the pasted JavaScript to be executed instead of being blocked.
Does this matter?
Lower severity and a low EPSS score (1.12%). Track it; it rarely justifies an emergency change on its own.
Description
Control characters prepended before "javascript:" URLs pasted in the addressbar can cause the leading characters to be ignored and the pasted JavaScript to be executed instead of being blocked. This could be used in social engineering and self-cross-site-scripting (self-XSS) attacks where users are convinced to copy and paste text into the addressbar. This vulnerability affects Firefox < 57.
- CVSS 3.0
- 6.1 MEDIUMCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- EPSS
- 1.12% probability · 66th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Affected
- mozilla/firefox
- Source
- security@mozilla.org
EPSS 1.1% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.securityfocus.com/bid/101832Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1039803Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1402896Issue Tracking, Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2017-24/Vendor Advisory
- http://www.securityfocus.com/bid/101832Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1039803Third Party Advisory, VDB Entry
- https://bugzilla.mozilla.org/show_bug.cgi?id=1402896Issue Tracking, Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2017-24/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.