CVE-2021-30533
MediumExploitedPublic exploitInsufficient 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.
Published May 28, 2021 · Updated Aug 4, 2026 · Also known as DEBIAN-CVE-2021-30533, UBUNTU-CVE-2021-30533
Key Facts
Patch immediately- CVE-2021-30533 is a medium-severity vulnerability (CVSS 6.5 v3.1) affecting Chrome (Google), Fedora (Fedoraproject), chromium (arch) and 17 more products.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Aug 16, 2021. Public exploit code is available.
- EPSS estimates a 17% probability of exploitation in the next 30 days.
- Fixed versions are available, including Chrome 91.0.4472.77, chromedriver 91.0.4472.77-bp153.2.3.1, chromedriver 91.0.4472.77-lp152.2.98.1.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
EPSS (30-day exploit likelihood)
17%
Higher than 97.0% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-30533 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Jun 27, 2022 | Jul 18, 2022 | Not reported |
| Industry KEV feed | Aug 16, 2021 | Jul 18, 2022 | Not reported |
| CIRCL KEV | Jun 27, 2022 | Jul 18, 2022 | Not reported |
| ENISA EUVD | Jun 27, 2022 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
61 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| ChromeGoogle | >= unspecified | 91.0.4472.77 |
| FedoraFedoraproject | 33, 34 | n/a |
| chromiumarch | See advisory | 91.0.4472.77-1 |
| operaarch | See advisory | 77.0.4054.60-1 |
| vivaldiarch | See advisory | 4.0.2312.24-1 |
Patched Releases
Chrome
91.0.4472.77
chromedriver
91.0.4472.77-bp153.2.3.1, 91.0.4472.77-lp152.2.98.1, 93.0.4577.82-1.1
chromium
91.0.4472.77-1, 91.0.4472.77-bp153.2.3.1, 91.0.4472.77-lp152.2.98.1, 91.0.4472.77-r0, 93.0.4577.82-1, 93.0.4577.82-1.1
chromium-browser
91.0.4472.77-0ubuntu0.18.04.1
libqt5-qtpdf-devel
5.15.6-2.1
libqt5-qtpdf-examples
5.15.6-2.1
libqt5-qtpdf-imports
5.15.6-2.1
libqt5-qtpdf-private-headers-devel
5.15.6-2.1
libqt5-qtwebengine
5.15.6-2.1
libqt5-qtwebengine-devel
5.15.6-2.1
libqt5-qtwebengine-examples
5.15.6-2.1
libqt5-qtwebengine-private-headers-devel
5.15.6-2.1
libQt5Pdf5
5.15.6-2.1
libQt5PdfWidgets5
5.15.6-2.1
opera
77.0.4054.60-1
qt5-qtwebengine
5.15.3_git20210510-r4, 5.15.3_git20211006-r0
ungoogled-chromium
113.0.5672.92-1.1
ungoogled-chromium-chromedriver
113.0.5672.92-1.1
vivaldi
4.0.2312.24-1
Timeline
Publicly disclosed
May 28, 2021
Added to Industry KEV feed
Aug 16, 2021
Added to CISA KEV
Jun 27, 2022
Added to CIRCL KEV
Jun 27, 2022
Added to ENISA EUVD
Jun 27, 2022
Last updated
Aug 4, 2026
Weakness Type
- CWE-863 Incorrect Authorization
References
- advisoryhttps://chromereleases.googleblog.com/2021/05/stable-channel-update-for-desktop_25.html
- advisoryhttps://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2021-31937
- advisoryGLSA-202107-06
- advisoryhttps://security-tracker.debian.org/tracker/CVE-2021-30533
- advisoryhttps://ubuntu.com/security/CVE-2021-30533
FAQ
Common Questions.
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.
Affected: Chrome (Google) versions >= unspecified; Fedora (Fedoraproject) versions 33, 34; chromium (arch), among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Aug 16, 2021.
Yes. It was added on Jun 27, 2022 with a federal remediation due date of Jul 18, 2022.
Public exploit code is available.
Fixed versions are available, including Chrome 91.0.4472.77, chromedriver 91.0.4472.77-bp153.2.3.1, chromedriver 91.0.4472.77-lp152.2.98.1.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Is CVE-2021-30533 Running On Your Attack Surface?
Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.
Request A Demo