Service delays via quadratic tuple-list reindentation
Published Sep 1, 2026 · Updated Sep 1, 2026
Algorithmic complexity in sqlparse before 0.6.0 allows attackers to delay reindentation by submitting crafted SQL tuple lists. ReindentFilter._get_offset() repeatedly flattens and joins an expanding statement prefix while calculating offsets for parenthesized tuples, producing quadratic CPU work. Exploitation requires attacker-controlled SQL to reach the opt-in reindentation path and can delay requests, reduce throughput, or starve workers without terminating the process.
Summary
What happened
Algorithmic complexity in sqlparse before 0.6.0 allows attackers to delay reindentation by submitting crafted SQL tuple lists. ReindentFilter._get_offset() repeatedly flattens and joins an expanding statement prefix while calculating offsets for parenthesized tuples, producing quadratic CPU work. Exploitation requires attacker-controlled SQL to reach the opt-in reindentation path and can delay requests, reduce throughput, or starve workers without terminating the process.
The record
- CVE
- CVE-2026-84305
- Published
- Sep 1, 2026
- Updated
- Sep 1, 2026
- Vendor
- Andi Albrecht
- Product
- sqlparse
- Classifications
- CWE-1333, T1499.004
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 1, 2026CVE publishedPublication date reported by the CVE source.
- Sep 1, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=< 0.6.0
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
- Reindent tuple-list CPU denial-of-service proof of conceptproof of concept · validated
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Technologies
Your stack
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Your stack
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