What’s Vulnerable › Vulnerabilities

CVE-2017-5389

• Severity: medium (CVSS 6.1 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2018-06-11 · updated 2026-06-17
• Weakness: CWE-601

Description

WebExtensions could use the "mozAddonManager" API by modifying the CSP headers on sites with the appropriate permissions and then using host requests to redirect script loads to a malicious site. This allows a malicious extension to then install additional extensions without explicit user permission. This vulnerability affects Firefox < 51.

Affected products

• Mozilla Firefox: before 51.0 — fixed in 51.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 51.0. Check the vendor advisory for mitigations.

References

• http://www.securityfocus.com/bid/95763
• http://www.securitytracker.com/id/1037693
• https://bugzilla.mozilla.org/show_bug.cgi?id=1308688
• https://www.mozilla.org/security/advisories/mfsa2017-01/
• http://www.securityfocus.com/bid/95763
• http://www.securitytracker.com/id/1037693
• https://bugzilla.mozilla.org/show_bug.cgi?id=1308688
• https://www.mozilla.org/security/advisories/mfsa2017-01/

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