Local socket hijacking via unauthenticated fallback connection
Published Jul 29, 2024 · Updated May 2, 2025
Race condition in CPython on Windows allows local users to hijack a socketpair connection through the loopback interface. In Lib/socket.py, the pure-Python socket.socketpair() fallback accepts the first AF_INET or AF_INET6 connection without verifying that its peer is the client socket it created. A malicious local peer that wins the connection race is returned as the server-side socket and can receive data intended for the internal socket pair.
Summary
What happened
Race condition in CPython on Windows allows local users to hijack a socketpair connection through the loopback interface. In Lib/socket.py, the pure-Python socket.socketpair() fallback accepts the first AF_INET or AF_INET6 connection without verifying that its peer is the client socket it created. A malicious local peer that wins the connection race is returned as the server-side socket and can receive data intended for the internal socket pair.
The record
- CVE
- CVE-2024-3219
- Published
- Jul 29, 2024
- Updated
- May 2, 2025
- Vendor
- Python Software Foundation
- Product
- CPython
- Classifications
- CWE-362, T1557
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 29, 2024CVE publishedPublication date reported by the CVE source.
- May 2, 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=0 <3.8.20
- Affected versionversion=3.10.0 <3.10.15
- Affected versionversion=3.11.0 <3.11.10
- Affected versionversion=3.12.0 <3.12.5
- Affected versionversion=3.13.0a1 <3.13.0rc1
- Affected versionversion=3.9.0 <3.9.20
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
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Weakness, pattern, technique
Public exploit references
- CPython injected socketpair authentication failure testproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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