CVE-2026-84305: andialbrecht sqlparse Inefficient Algorithmic Complexity

Vulnerability summary

CVE-2026-84305 is a medium (CVSS 5.1) Inefficient Algorithmic Complexity vulnerability in andialbrecht sqlparse. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8% of scored vulnerabilities.

Timeline

1. 01-09-2026
   PublishedVulnerability first disclosed.
2. 01-09-2026
   Last modifiedVulnerability information updated.

Description

sqlparse is a non-validating SQL parser module for Python. Prior to 0.6.0, sqlparse.format(sql, reindent=True) and sqlformat --reindent route attacker-controlled parenthesized tuple lists through ReindentFilter._get_offset() in sqlparse/filters/reindent.py, where _flatten_up_to_token() repeatedly rebuilds and joins the statement prefix. Thousands of offset calculations walk an expanding token tree, producing quadratic CPU consumption for inputs that remain below MAX_GROUPING_TOKENS and causing request delays, reduced throughput, or worker starvation. This issue is fixed in version 0.6.0.

• CWE-407Inefficient Algorithmic ComplexityAn algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.