Mozilla · Firefox · CVE-2018-5131
**Name of the Vulnerable Software and Affected Versions**
Firefox ESR versions prior to 52.7
Firefox versions prior to 59
**Description**
The issue is related to the "fetch()" API, which under certain circumstances can return transient local copies of resources that were sent with a "no-store" or "no-cache" cache header, instead of downloading a copy from the network. This can result in previously stored, locally cached data of a website being accessible to users if they share a common profile while browsing. The vulnerability can be exploited by a remote attacker to gain unauthorized access to protected information.
**Recommendations**
For Firefox ESR versions prior to 52.7, update to version 52.7 or later.
For Firefox versions prior to 59, update to version 59 or later.