CVE-2017-7840 Cross-site scripting in Firefox
Attackers can inject JavaScript into exported bookmark files, leading to script execution when opened, requiring user interaction for social engineering.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2017-7840?
CVE-2017-7840 is a medium-severity cross-site scripting vulnerability in Mozilla Firefox, published on 11 Jun 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
JavaScript can be injected into an exported bookmarks file by placing JavaScript code into user-supplied tags in saved bookmarks. If the resulting exported HTML file is later opened in a browser this JavaScript will be executed. This could be used in social engineering and self-cross-site-scripting (self-XSS) attacks if users were convinced to add malicious tags to bookmarks, export them, and then open the resulting file. This vulnerability affects Firefox < 57.
Weakness: CWE-79
Which versions are affected by CVE-2017-7840?
It affects 1 product.
Products include Mozilla Firefox.
How do I fix CVE-2017-7840?
Upgrade to a fixed version.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2017-7840 being exploited?
There is no known exploitation of CVE-2017-7840 in the wild and no public exploit code.
Other vulnerabilities in Mozilla Firefox
Sources
Also known as GHSA-gx4h-qpc9-477w, UBUNTU-CVE-2017-7840.