CVE-2021-30533
MEDIUMCISA KEVEPSS 97th pctlDescription
Insufficient policy enforcement in PopupBlocker in Google Chrome prior to 91.0.4472.77 allowed a remote attacker to bypass navigation restrictions via a crafted iframe.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Exploit Intelligence
Very high risk: more likely to be exploited than 97% of all known CVEs.
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.
Apply updates per vendor instructions.
Remediation due: 2022-07-18
References
Related Vulnerabilities
Other CWE-863 (Incorrect Authorization) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-22518 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2023-38035 | Critical | 9.8 | 100% | KEV + Ransom | - |
| CVE-2022-46169 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2024-38856 | Critical | 9.8 | 99% | KEV | Fix |
| CVE-2025-29927 | Critical | 9.1 | 99% | - | Fix |
| CVE-2020-36289 | Medium | 5.3 | 99% | - | Fix |
Common questions
How do I fix CVE-2021-30533?
Published advisories record a fix for 8 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2021-30533 being actively exploited?
Yes. CVE-2021-30533 is listed in the CISA Known Exploited Vulnerabilities catalog, which means exploitation has been observed in the wild. US federal agencies were required to remediate it by 2022-07-18. Treat it as a priority whatever its CVSS score says.
How severe is CVE-2021-30533?
CVE-2021-30533 has a CVSS v3 base score of 6.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-30533 affect?
Published advisories record a fix for chromium (Debian), Google Chrome (Windows application), Google Chrome (EXE) (Windows application), Google Chrome Beta (Windows application), and 4 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2021-30533
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-24.