Vulnerability

CVE-2021-30533

Medium· 6.5KEVCVSS6.5EPSS17%

.rules3/5

Google Chromium PopupBlocker Security Bypass Vulnerability

Google Chromium PopupBlocker contains an insufficient policy enforcement vulnerability that allows a remote attacker to bypass navigation restrictions via a crafted iframe. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.

Threat signal

78/100

High

Severity

medium

CVSS

6.5

EPSS

17%

Active

KEV

CISA KEV — actively exploited

1426d overdue

AffectedGoogle — Chromium PopupBlocker

Added to KEV

2022-06-27

Federal patch due (BOD 22-01)

2022-07-18

Required action (CISA verbatim)

Apply updates per vendor instructions.

Vendor advisory + references

https://nvd.nist.gov/vuln/detail/CVE-2021-30533

CISA description: “Google Chromium PopupBlocker contains an insufficient policy enforcement vulnerability that allows a remote attacker to bypass navigation restrictions via a crafted iframe. This vulnerability could affect multiple web browsers that utilize Chromium, including, but not limited to, Google Chrome, Microsoft Edge, and Opera.”

CVSS

v3.1Open in FIRST calculator →

6.5/ 10MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Attack VectorNetworkExploitable remotely over the internet — no local access needed.
Attack ComplexityLowNo special conditions — exploit works reliably.
Privileges RequiredNoneUnauthenticated — no credentials needed.
User InteractionRequiredRequires user action (click, file open, etc).
ScopeUnchangedImpact contained to the vulnerable component.
Confidentiality ImpactNoneNo confidentiality impact.
Integrity ImpactHighTotal compromise of integrity — full data modification possible.
Availability ImpactNoneNo availability impact.

EPSS

Exploit prediction · 30-day horizonFIRST.org →

16.7%

probability of exploitation in next 30 days

p95

higher than 95% of all CVEs

3-day trend↑ 0pp

Above the FIRST 'patch on a priority schedule' threshold.

Vendor VEX

No VEX statements published for CVE-2021-30533. Vendors publish VEX (Vulnerability Exploitability eXchange) to assert per-product whether a CVE is actually exploitable in their distribution.

SSVCAttend

Active exploitation with limited impact — coordinate patching

exploitation: active
automatable: no
impact: partial
mission: support

Lifecycle

2022-06-27Added to CISA KEVransomware: Unknown
2022-06-27Published
2022-07-18Federal patch due (BOD 22-01)
2026-06-12Last modified1 source

No source-event history recorded yet. New revisions will appear here as ingestors re-fetch this CVE.