Remote code execution via freed event context
Published Jul 8, 2021 · Updated Aug 3, 2024
Use-after-free in WebKitGTK before 2.30.6 allows remote attackers to execute code by luring a victim to malicious HTML. EventTarget::fireEventListeners dereferences a ScriptExecutionContext whose Document has already been freed during DOM mutation and media-group event processing. Exploitation requires a victim to load the crafted page; controlled heap reuse turns the dangling reference into code execution in the WebKit content process.
Summary
What happened
Use-after-free in WebKitGTK before 2.30.6 allows remote attackers to execute code by luring a victim to malicious HTML. EventTarget::fireEventListeners dereferences a ScriptExecutionContext whose Document has already been freed during DOM mutation and media-group event processing. Exploitation requires a victim to load the crafted page; controlled heap reuse turns the dangling reference into code execution in the WebKit content process.
The record
- CVE
- CVE-2021-21806
- Published
- Jul 8, 2021
- Updated
- Aug 3, 2024
- Vendor
- The WebKitGTK Team
- Product
- WebKitGTK
- Classifications
- CWE-416, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 8, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record 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=Webkit WebKitGTK 2.30.3
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.
Public exploit references
- Talos fireEventListeners proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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