CVE-2021-21223 [Critical] | Integer Overflow in Chrome

CVE-2021-21223 is rated Moderate Risk (63.1/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.44%). Review affected assets and schedule remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	1.16%	1.44%	+0.28%
2	2025-12-18	1.63%	1.16%	-0.47%
3	2025-05-12	—	1.63%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

1.16%

1.44%

+0.28%

2025-12-18

1.63%

1.16%

-0.47%

2025-05-12

—

1.63%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.6	3.1	CRITICAL	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H` 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:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	6.0	[email protected]
6.8	2.0	MEDIUM	`AV:N/AC:M/Au:N/C:P/I:P/A:P` 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:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	8.6	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.6

3.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H 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:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

6.0

[email protected]

6.8

2.0

MEDIUM

AV:N/AC:M/Au:N/C:P/I:P/A:P 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:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

8.6

6.4

[email protected]

OS Trackers for CVE-2021-21223

vendor	priority	summary	link
`alpine`	critical	CVE-2021-21223: 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-2021-21223
`debian`	not yet assigned	CVE-2021-21223 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-2021-21223
`gentoo`	normal	CVE-2021-21223: 1 GLSA(s) (202104-08), 2 atom(s) (www-client/chromium, www-client/google-chrome); latest impact normal.	https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-21223
`ubuntu`	medium	CVE-2021-21223 medium priority: Ubuntu including 1 source packages (chromium-browser), 9 status rows across 9 suites (bionic, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): not-affected 4, DNE 2, released 2, ignored 1.	https://ubuntu.com/security/CVE-2021-21223

Affected software / configurations for CVE-2021-21223

Vendor	Product	Version	Raw CPE
google	chrome	< 90.0.4430.85	cpe:2.3:a:google:chrome::::::::
debian	debian_linux	10.0	cpe:2.3:o:debian:debian_linux:10.0:::::::*
fedoraproject	fedora	32	cpe:2.3:o:fedoraproject:fedora:32:::::::*
fedoraproject	fedora	33	cpe:2.3:o:fedoraproject:fedora:33:::::::*
fedoraproject	fedora	34	cpe:2.3:o:fedoraproject:fedora:34:::::::*

References for CVE-2021-21223

URL	Tags
https://chromereleases.googleblog.com/2021/04/stable-channel-update-for-desktop_20.html	Release Notes Third Party Advisory
https://crbug.com/1195308	Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EAJ42L4JFPBJATCZ7MOZQTUDGV4OEHHG/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U3GZ42MYPGD35V652ZPVPYYS7A7LVXVY/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VUZBGKGVZADNA3I24NVG7HAYYUTOSN5A/
https://security.gentoo.org/glsa/202104-08	Third Party Advisory
https://www.debian.org/security/2021/dsa-4906	Third Party Advisory

URL

CVE-2021-21223

Exploit prediction scoring system (EPSS) score for CVE-2021-21223

Common vulnerability scoring system (CVSS) metrics for CVE-2021-21223

Weakness enumeration for CVE-2021-21223

OS Trackers for CVE-2021-21223

Affected software / configurations for CVE-2021-21223

References for CVE-2021-21223