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CVE-2020-6823

24
FAUCET Score

CVE-2020-6823 is a critical vulnerability affecting Mozilla Firefox versions prior to 75. A malicious browser extension could exploit this flaw by manipulating the redirect_uri in browser.identity.launchWebAuthFlow, thereby gaining unauthorized access to a user's authentication code and subsequently their service provider account. With a CVSS score of 9.8 (CRITICAL), this vulnerability presents a high risk due to its network-based attack vector, low attack complexity, and potential for complete compromise of confidentiality, integrity, and availability. While there is no evidence of active exploitation (KEV: No) or public exploit code (Metasploit, Nuclei, ExploitDB: None), the vulnerability has garnered significant community discussion and media coverage, indicating awareness within the security community.

Impacted Technologies

VendorProductVersion(s)CPE
< 75.0CPE matchmatch criteria
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*
< 75CPE match
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.61%
Probability of exploitation in next 30 days
EPSS Percentile
73.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0161 is in the 61st percentile among its peer group of 36,897 CVEs.

Social Chatter

No social media mentions found for this CVE.

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (4)

mozillavendor investigatingvia nvd_reference
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: firefox
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: firefox
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: firefox

Vendor Advisories (1)

redhatCVE-2020-6823Moderate

Mozilla: Malicious Extension could obtain auth codes from OAuth login flows

Apr 10, 2020

References

bugzilla.mozilla.org / show_bug.cgi
Issue TrackingVendor Advisory
mozilla.org / security/advisories/mfsa2020-12
Third Party Advisory