CVE-2021-30538
Published: April 11, 2026
Official Description
Insufficient policy enforcement in content security policy in Google Chrome prior to 91.0.4472.77 allowed a remote attacker to bypass content security policy via a crafted HTML page.
Risk Analysis
This vulnerability in Google Chrome allows a remote attacker to bypass content security policies by crafting a malicious HTML page. Since it's confirmed to be exploited in the wild (is_in_kev is true), it poses an immediate and significant risk to users.
Active exploitation of this vulnerability has been observed in the wild, and it is listed in CISA's KEV catalog, indicating confirmed real-world impact. A remote attacker can exploit this flaw via a crafted HTML page.
Users should update Google Chrome to version 91.0.4472.77 or later to address this vulnerability. Regularly updating web browsers is crucial for maintaining security.
Technical Analysis
CVE-2021-30538 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2021-30538 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-30538 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1