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CVE-2021-21174

28
FAUCET Score

CVE-2021-21174 is a high-severity vulnerability in Google Chrome versions prior to 89.0.4389.72, affecting various Debian and Fedora distributions. This flaw, categorized as an "inappropriate implementation in Referrer," allows a remote attacker to bypass navigation restrictions through a specially crafted HTML page. With a CVSS score of 8.8, it carries high impacts on confidentiality, integrity, and availability, requiring user interaction but being network-exploitable with low attack complexity. While there is no known public exploit code or Metasploit/Nuclei modules, it was reportedly an actively exploited zero-day at the time of its discovery, garnering significant community discussion and media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 89.0.4389.72CPE matchmatch criteria
cpe:2.3:a:google:chrome:*:*:*:*:*:*:*:*
32CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
33CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
10.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.8HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.50%
Probability of exploitation in next 30 days
EPSS Percentile
71.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0150 is in the 70th percentile among its peer group of 14,875 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.1 Security Researcher mentions.

Remediation

Vendor Patches (1)

googlevendor investigatingvia nvd_reference
View patch

Vendor Advisories (1)

microsoft2021-Mar/CVE-2021-21174

Chromium CVE-2021-21174: Inappropriate implementation in Referrer

Mar 9, 2021

References

chromereleases.googleblog.com / 2021/03/stable-channel-update-for-desktop.html
Release NotesVendor Advisory
crbug.com / 1158010
ExploitIssue TrackingPatchPermissions RequiredThird Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/BBT54RKAE5XLMWSHLVUKJ7T2XHHYMXLH
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/FE5SIKEVYTMDCC5OSXGOM2KRPYLHYMQX
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/LCIDZ77XUDMB2EBPPWCQXPEIJERDNSNT
security.gentoo.org / glsa/202104-08
Third Party Advisory
debian.org / security/2021/dsa-4886
Third Party Advisory