SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2017-7834

A "data:" URL loaded in a new tab did not inherit the Content Security Policy (CSP) of the original page, allowing for bypasses of the policy including the execution of JavaScript.

MEDIUM 6.1EPSS 1.51%

Does this matter?

Lower severity and a low EPSS score (1.51%). Track it; it rarely justifies an emergency change on its own.

Description

A "data:" URL loaded in a new tab did not inherit the Content Security Policy (CSP) of the original page, allowing for bypasses of the policy including the execution of JavaScript. In prior versions when "data:" documents also inherited the context of the original page this would allow for potential cross-site scripting (XSS) attacks. 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
1.51% probability · 74th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-79
Affected
mozilla/firefox
Source
security@mozilla.org
EPSS trend
0%3%5%27 October 2026: 1.51%27 October 202627 October 2026

EPSS 1.5% 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.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.