CVE-2020-15666

Name: CVE-2020-15666
Creator: NVD / NIST
Published: 2020-10-01T19:15:13.203+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.22%

Last modified Jun 17, 2026

CVE-2020-15666 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 1.22% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

EPSS Probability

1.22%

64.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-209

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 80.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1450853Exploit, Issue Tracking, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-36/Release Notes, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-39/Release Notes, Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1450853Exploit, Issue Tracking, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-36/Release Notes, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-39/Release Notes, Vendor Advisory

Timeline

Published: Oct 1, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-15666?

How severe is CVE-2020-15666?

CVE-2020-15666 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.22% probability of exploitation in the next 30 days.

How do I fix CVE-2020-15666?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-15666?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST