What’s Vulnerable › Vulnerabilities

CVE-2020-15666

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2020-10-01 · updated 2026-08-19
• Weakness: CWE-209

Description

When trying to load a non-video in an audio/video context the exact status code (200, 302, 404, 500, 412, 403, etc.) was disclosed via the MediaError Message. This level of information leakage is inconsistent with the standardized onerror/onsuccess disclosure and can lead to inferring login status to services or device discovery on a local network among other attacks. This vulnerability affects Firefox < 80 and Firefox for Android < 80.

Affected products

• Mozilla Firefox: before 80.0 — fixed in 80.0
• Mozilla Firefox for Android: before 80.0 — fixed in 80.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 80.0; Mozilla Firefox for Android 80.0. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1450853
• https://www.mozilla.org/security/advisories/mfsa2020-36/
• https://www.mozilla.org/security/advisories/mfsa2020-39/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1450853
• https://www.mozilla.org/security/advisories/mfsa2020-36/
• https://www.mozilla.org/security/advisories/mfsa2020-39/

Get alerted when CVE-2020-15666 or the next vulnerability affects your stack