CVE-2026-71491: sqlparse: Quadratic O(n²) DoS in group_comments

Severity: high (CVSS 8.7 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-17 · updated 2026-10-23
Weakness: CWE-400

Description

sqlparse is a non-validating SQL parser module for Python. Prior to 0.6.0, group_comments in sqlparse/engine/grouping.py repeatedly rescans comment-only statements before the MAX_GROUPING_TOKENS guard, causing quadratic CPU consumption through sqlparse.parse() and sqlparse.format(sql, strip_comments=True). This issue is fixed in version 0.6.0.

Affected products

Pypi Sqlparse: before 0.6.0; 0.1.0, 0.1.1, 0.1.10, 0.1.11, 0.1.12, 0.1.13 (+32) — fixed in 0.6.0
andialbrecht sqlparse: before 0.6.0

How to fix

Upgrade to a fixed version: Pypi Sqlparse 0.6.0. Check the vendor advisory for mitigations.

References

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