What’s Vulnerable › Vulnerabilities

CVE-2018-5134

• Severity: high (CVSS 7.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-06-11 · updated 2026-06-17
• Weakness: CWE-200

Description

WebExtensions may use "view-source:" URLs to view local "file:" URL content, as well as content stored in "about:cache", bypassing restrictions that only allow WebExtensions to view specific content. This vulnerability affects Firefox < 59.

Affected products

• Mozilla Firefox: before 59.0 — fixed in 59.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 59.0. Check the vendor advisory for mitigations.

References

• http://www.securityfocus.com/bid/103386
• http://www.securitytracker.com/id/1040514
• https://bugzilla.mozilla.org/show_bug.cgi?id=1429379
• https://usn.ubuntu.com/3596-1/
• https://www.mozilla.org/security/advisories/mfsa2018-06/
• http://www.securityfocus.com/bid/103386
• http://www.securitytracker.com/id/1040514
• https://bugzilla.mozilla.org/show_bug.cgi?id=1429379
• https://usn.ubuntu.com/3596-1/
• https://www.mozilla.org/security/advisories/mfsa2018-06/

Get alerted when CVE-2018-5134 or the next vulnerability affects your stack