Heap-address disclosure via CopyPolicyToTarget race
Published Jan 8, 2020 · Updated Aug 5, 2024
Race condition in Mozilla Firefox before 72 and Firefox ESR before 68.4 allows attackers controlling a content process to disclose heap addresses. During new-process bootstrapping, CopyPolicyToTarget exposes shared process state while another renderer can access the process, creating a race that leaks a valid parent-process heap pointer. Existing code execution in a Windows content process is required, and the disclosure reveals memory layout that can help bypass ASLR in a chained exploit.
Summary
What happened
Race condition in Mozilla Firefox before 72 and Firefox ESR before 68.4 allows attackers controlling a content process to disclose heap addresses. During new-process bootstrapping, CopyPolicyToTarget exposes shared process state while another renderer can access the process, creating a race that leaks a valid parent-process heap pointer. Existing code execution in a Windows content process is required, and the disclosure reveals memory layout that can help bypass ASLR in a chained exploit.
The record
- CVE
- CVE-2019-17021
- Published
- Jan 8, 2020
- Updated
- Aug 5, 2024
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- CWE-362, T1211
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 8, 2020CVE publishedPublication date reported by the CVE source.
- Aug 5, 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=before 72
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
- race.zip heap-address disclosure reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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