CVE-2017-5386 Information disclosure in Firefox

What is CVE-2017-5386?

CVE-2017-5386 is a high-severity vulnerability in Debian Debian Linux, published on 11 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

WebExtension scripts can use the "data:" protocol to affect pages loaded by other web extensions using this protocol, leading to potential data disclosure or privilege escalation in affected extensions. This vulnerability affects Firefox ESR < 45.7 and Firefox < 51.

Which versions are affected by CVE-2017-5386?

It affects 8 products.

Products include Debian Debian Linux, Mozilla Firefox, Redhat Enterprise Linux, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus and 2 more.

How do I fix CVE-2017-5386?

Upgrade to a fixed version.

Is CVE-2017-5386 being exploited?

There is no known exploitation of CVE-2017-5386 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2017-5386, GHSA-mjv5-g7c5-w9hq, UBUNTU-CVE-2017-5386.