Code execution via stale interceptor property lookup
Published Jun 15, 2021 · Updated Oct 21, 2025
Type confusion in V8 in Google Chrome before 91.0.4472.101 allows remote attackers to corrupt heap memory via a crafted HTML page. During property assignment, an HTMLEmbedElement interceptor can run JavaScript that adds the target property, but SetPropertyInternal retains the stale absent result and AddDataProperty creates a second descriptor, corrupting the object. A user must load attacker-controlled content; the resulting JIT type confusion supports out-of-bounds read and write and payload execution, while the browser sandbox limits post-exploitation access unless separately escaped.
Summary
What happened
Type confusion in V8 in Google Chrome before 91.0.4472.101 allows remote attackers to corrupt heap memory via a crafted HTML page. During property assignment, an HTMLEmbedElement interceptor can run JavaScript that adds the target property, but SetPropertyInternal retains the stale absent result and AddDataProperty creates a second descriptor, corrupting the object. A user must load attacker-controlled content; the resulting JIT type confusion supports out-of-bounds read and write and payload execution, while the browser sandbox limits post-exploitation access unless separately escaped.
The record
- CVE
- CVE-2021-30551
- Published
- Jun 15, 2021
- Updated
- Oct 21, 2025
- Vendor
- Google Cloud
- Product
- Google Chrome
- Classifications
- CWE-843, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 15, 2021CVE publishedPublication date reported by the CVE source.
- Nov 3, 2021Exploitation reportedCISA Known Exploited Vulnerabilities entry
- Oct 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <91.0.4472.101
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Google Project Zero proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- Browser exploit-chain componentexploit chain
- Google-reported in-the-wild exploitationreported exploitation
- CISA Known Exploited Vulnerabilities entryknown exploited catalog
Technologies
Your stack
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Your stack
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