Service interruption via recursive token flattening
Published Apr 30, 2024 · Updated Nov 3, 2025
Uncontrolled recursion in sqlparse before 0.5.0 allows remote attackers to interrupt services that parse deeply nested SQL input. TokenList.flatten() recursively descends every nested token group without a depth guard, exhausting Python's recursion limit and raising RecursionError. Exposure requires an application to pass attacker-controlled SQL text to sqlparse.parse(); the exception can terminate the parsing operation or its hosting request.
Summary
What happened
Uncontrolled recursion in sqlparse before 0.5.0 allows remote attackers to interrupt services that parse deeply nested SQL input. TokenList.flatten() recursively descends every nested token group without a depth guard, exhausting Python's recursion limit and raising RecursionError. Exposure requires an application to pass attacker-controlled SQL text to sqlparse.parse(); the exception can terminate the parsing operation or its hosting request.
The record
- CVE
- CVE-2024-4340
- Published
- Apr 30, 2024
- Updated
- Nov 3, 2025
- Vendor
- Andi Albrecht
- Product
- sqlparse
- Classifications
- CWE-674, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 30, 2024CVE publishedPublication date reported by the CVE source.
- Nov 3, 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
- Affected versionversion=0 <0.5.0
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
- GHSA deeply nested bracket proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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