CVE-2021-4059

Insufficient data validation in loader in Google Chrome prior to 96.0.4664.93 allowed a remote attacker to leak cross-origin data via a crafted HTML page.

Published: 2021-12-23 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-4059 is rated Moderate Risk (53.9/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.56%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-4059

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-12-10 1.98% 1.56% -0.41%
2 2025-11-21 0.96% 1.98% +1.02%
3 2025-11-18 — 0.96% —

Full EPSS history (22 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-4059

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-4059

OS Trackers for CVE-2021-4059

vendor priority summary link
alpine medium CVE-2021-4059: 1 source package rows (qt5-qtwebengine); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2021-4059
debian not yet assigned CVE-2021-4059 not yet assigned priority: Debian including 1 source packages (chromium), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-4059
gentoo high CVE-2021-4059: 1 GLSA(s) (202208-25), 4 atom(s) (dev-qt/qtwebengine, www-client/chromium, www-client/google-chrome, www-client/microsoft-edge); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-4059
ubuntu medium CVE-2021-4059 medium priority: Ubuntu including 1 source packages (chromium-browser), 8 status rows across 8 suites (bionic, focal, hirsute, impish, jammy, trusty, upstream, xenial): not-affected 3, DNE 2, released 2, ignored 1. https://ubuntu.com/security/CVE-2021-4059

Affected software / configurations for CVE-2021-4059

Vendor Product Version Raw CPE
google chrome < 96.0.4664.93 cpe:2.3:a:google:chrome:*:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2021-4059

cvelogic Threat Intelligence