What’s Vulnerable › Vulnerabilities

CVE-2020-12390

• Severity: critical (CVSS 9.8 v3.1)
• 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: 2020-05-26 · updated 2026-06-17
• Weakness: CWE-502

Description

Incorrect origin serialization of URLs with IPv6 addresses could lead to incorrect security checks. This vulnerability affects Firefox < 76.

Affected products

• Mozilla Firefox: before 76.0 — fixed in 76.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 76.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1141959
• https://www.mozilla.org/security/advisories/mfsa2020-16/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1141959
• https://www.mozilla.org/security/advisories/mfsa2020-16/

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