6.5

CVE-2021-30533: Google Chromium PopupBlocker Security Bypass Vulnerability

KEV
Analyzed
AliasesUBUNTU-CVE-2021-30533DEBIAN-CVE-2021-30533ALPINE-CVE-2021-30533
Published 07-06-2021Last modified 21-10-2025

Vulnerability summary

CVE-2021-30533 is a medium (CVSS 6.5) Incorrect Authorization vulnerability in Google Chromium PopupBlocker. It is known to be exploited: CISA lists it, first on 27-06-2022. EPSS estimates a 16.74% chance of exploitation in the next 30 days, higher than 97% of scored vulnerabilities. 1 public exploit is recorded.

Priority
Act nowlisted as exploited

Listed as exploited by CISA (27-06-2022)

Source freshness unavailable

How is this decided?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
16.74%
0%100%
Medium · 0.00 pp in 30 days
KEVExploited in the wildCritical · listed in 1 catalog
RansomwareNot flaggedNo ransomware use recorded.
Public exploits1reference

Advisory lineage

Upstream 0 · Downstream 4 · Related 4
OPENSUSE-SU-2021:0825-1OPENSUSE-SU-2021:0840-1OPENSUSE-SU-2024:10681-1OPENSUSE-SU-2024:12948-1

Timeline

  1. 07-06-2021
    PublishedVulnerability first disclosed.
  2. 27-06-2022
    Added to CISA KEVExploitedGoogle Chromium PopupBlocker Security Bypass Vulnerability
  3. 18-07-2022
    CISA remediation dueDeadline passedApply updates per vendor instructions.
  4. 21-10-2025
    Last modifiedVulnerability information updated.

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.

CVSS metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

16.74%

Chance of exploitation in the next 30 days

Percentile

97%

Versus all other CVEs

30-day change

No change 0.00 pp

From 16.74% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
27-06-2022
Federal due date
18-07-2022
ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

CISA required action

Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2021-30533

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (crbug.com)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Alpine2 products
  • chromium< 91.0.4472.77-r0
  • qt5-qtwebengine< 5.15.3_git20211006-r0 | < 5.15.3_git20210510-r4
Debian1 product
  • chromium< 93.0.4577.82-1
Fedoraproject1 product
Google1 product
  • chrome≥ unspecified, < 91.0.4472.77 | < 91.0.4472.77
Ubuntu1 product
  • chromium-browser< 91.0.4472.77-0ubuntu0.18.04.1

5 vendors · 6 products

References

11 links
Show all 11 references