Privileged-process out-of-bounds write via unchecked length addition
Published Sep 27, 2023 · Updated Feb 13, 2025
Integer overflow in Firefox before 118 allows remote attackers to corrupt privileged-process memory through Alternate Services traffic. TransactionObserver::OnDataAvailable adds two 32-bit lengths without an overflow check, underallocates mWKResponse, then copies attacker-controlled bytes past its heap buffer. Exploitation requires the non-default network.http.altsvc.oe preference and a sufficiently long privileged main-thread stall.
Summary
What happened
Integer overflow in Firefox before 118 allows remote attackers to corrupt privileged-process memory through Alternate Services traffic. TransactionObserver::OnDataAvailable adds two 32-bit lengths without an overflow check, underallocates mWKResponse, then copies attacker-controlled bytes past its heap buffer. Exploitation requires the non-default network.http.altsvc.oe preference and a sufficiently long privileged main-thread stall.
The record
- CVE
- CVE-2023-5173
- Published
- Sep 27, 2023
- Updated
- Feb 13, 2025
- Vendor
- Mozilla
- Product
- Firefox
- Classifications
- T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 27, 2023CVE publishedPublication date reported by the CVE source.
- Feb 13, 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 <118
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
- Bug 1823172 proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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