CVE-2020-6823

Name: CVE-2020-6823
Creator: NVD / NIST
Published: 2020-04-24T16:15:13.633+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.61%

Last modified Jun 17, 2026

CVE-2020-6823 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. A malicious extension could have called <code>browser.identity.launchWebAuthFlow</code>, controlling the redirect_uri, and through the Promise returned, obtain the Auth code and gain access to the user's account at the service provider. This vulnerability affects Firefox < 75.. EPSS estimates a 1.61% chance of exploitation in the next 30 days.

Description

A malicious extension could have called <code>browser.identity.launchWebAuthFlow</code>, controlling the redirect_uri, and through the Promise returned, obtain the Auth code and gain access to the user's account at the service provider. This vulnerability affects Firefox < 75.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

1.61%

72.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-862

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 75.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1614919Issue Tracking, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-12/Third Party Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1614919Issue Tracking, Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-12/Third Party Advisory

Timeline

Published: Apr 24, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-6823?

How severe is CVE-2020-6823?

CVE-2020-6823 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.61% probability of exploitation in the next 30 days.

How do I fix CVE-2020-6823?

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-2020-6823?

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

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Source: NVD / NIST