CVE-2017-7787 Information disclosure in Firefox

What is CVE-2017-7787?

CVE-2017-7787 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

Same-origin policy protections can be bypassed on pages with embedded iframes during page reloads, allowing the iframes to access content on the top level page, leading to information disclosure. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

Weakness: CWE-200

Which versions are affected by CVE-2017-7787?

It affects 10 products.

Products include Debian Debian Linux, Mozilla Firefox, Mozilla Firefox Esr, Mozilla Thunderbird, Redhat Enterprise Linux, Redhat Enterprise Linux Desktop and 4 more.

How do I fix CVE-2017-7787?

Upgrade to a fixed version.

Is CVE-2017-7787 being exploited?

There is no known exploitation of CVE-2017-7787 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-2017-7787, GHSA-6g35-2rw4-ch3p, UBUNTU-CVE-2017-7787.