Google · Chromium PopupBlocker
CVE-2021-30533
Google Chromium PopupBlocker Security Bypass Vulnerability
What it is
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.
CISA: 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.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: July 18, 2022
- Added to the CISA list
- June 27, 2022
- Published
- June 7, 2021
- Severity
- Medium 6.5 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 17% in the top 3.0% of all known vulnerabilities
- Weakness
- CWE-863
- More details
- NVD · CVE.org · CISA
All references (5)
- https://security.gentoo.org/glsa/202107-06
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PAT6EOXVQFE6…
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ETMZL6IHCTCT…
- https://chromereleases.googleblog.com/2021/05/stable-channel-update-for-desktop_25.html
- https://crbug.com/1145553
More exploited flaws from Google
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Oct 27, 2026 | Unchecked Return Value | Brotli | Critical 9.2 | 55% |
| Sep 16, 2026 | Improper Authorization | Pixel | High 8.8 | 0.6% |
| Sep 9, 2026 | Out of Bounds Write | Chromium V8 | High 8.8 | 3.5% |
| Sep 4, 2026 | Type Confusion | Chromium V8 | High 8.8 | 1.8% |
| Jun 9, 2026 | Out-of-Bounds Read and Write | Chromium V8 | High 8.8 | 2.4% |
| Apr 1, 2026 | Use-After-Free | Dawn | High 8.8 | 14% |
| Mar 13, 2026 | Out-of-Bounds Write | Skia | High 8.8 | 2.3% |
| Mar 13, 2026 | Improper Restriction of Operations Within the Bounds of a Memory Buffer | Chromium V8 | High 8.8 | 2.7% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.