SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

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.

MEDIUM 6.1EPSS 1.14%

Does this matter?

Lower severity and a low EPSS score (1.14%). 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
1.14% probability · 65th percentile
CISA KEV
Not listed
Weakness
CWE-79
Affected
mozilla/firefox
Source
security@mozilla.org

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.