# CVE-2026-84305: sqlparse quadratic CPU consumption in reindent filter

Source: https://junglewise.ai/threats/cve-2026-84305-sqlparse-quadratic-cpu-consumption-in-reindent-filter  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-01. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-84305 · Severity: medium · CVSS 4 · Published 2026-09-01

sqlparse is a Python library that parses and formats SQL statements. When the optional SQL reindentation feature is enabled, an attacker can craft a specially-sized SQL statement with nested tuples that causes the formatter to consume multiple seconds of CPU per request, potentially stalling worker processes and degrading service availability through resource exhaustion.

Technologies: [sqlparse (PyPI)](https://junglewise.ai/threats/technologies/sqlparse). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-84305 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-84305 being exploited in the wild.

**How severe is CVE-2026-84305?** Medium severity, with a CVSS score of 4, published 1 September 2026.

**Which products and versions are affected?** sqlparse (PyPI) <= 0.5.5, ECOSYSTEM:introduced=0,fixed=0.6.0.

**Is there a fix for CVE-2026-84305?** Yes. sqlparse (PyPI): upgrade to 0.6.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-84305 attacked?** It is attacked with local access.

**Am I affected by CVE-2026-84305?** Check whether you run sqlparse (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- sqlparse (PyPI): upgrade to 0.6.0 or later

  ```sh
  pip install "sqlparse>=0.6.0"
  ```


## Technical details

The vulnerability is an algorithmic complexity flaw (CWE-407) in the `ReindentFilter` class. When reindentation is enabled via `sqlparse.format(sql, reindent=True)` or the `--reindent` CLI flag, the `_get_offset()` method repeatedly reconstructs token trees from the statement start to calculate output positions. Processing a parenthesized tuple list that remains just below the grouping-token cap triggers quadratic behavior: later offset calculations redundantly traverse increasingly large portions of the token tree. An attacker who controls SQL input can supply a ~16 KB payload with ~1425 tuples to cause multi-second delays (demonstrated as 4+ seconds vs. 0.6 seconds baseline). The attack requires the reindentation option to be explicitly enabled; sqlparse itself does not expose network interfaces. Impact is CPU starvation and request delays; no code execution, data exposure, or integrity compromise occurs. Patch available in version 0.6.0.

## Affected products

- andialbrecht sqlparse <= 0.5.5

## Identifiers

- CVE-2026-84305
- GHSA-cfqr-cjx5-5jcm
- PYSEC-2026-3923

## Timeline

- 2026-09-01: disclosed: Published to GitHub Advisory Database
- 2026-09-01: patched: Fixed in sqlparse 0.6.0

## References

- [https://api.github.com/users/7thParkk](https://api.github.com/users/7thParkk)
- [https://github.com/7thParkk](https://github.com/7thParkk)
- [https://api.github.com/users/7thParkk/gists%7B/gist_id%7D](https://api.github.com/users/7thParkk/gists%7B/gist_id%7D)
- [https://api.github.com/users/7thParkk/repos](https://api.github.com/users/7thParkk/repos)
- [https://avatars.githubusercontent.com/u/91473103?v=4](https://avatars.githubusercontent.com/u/91473103?v=4)
- [https://api.github.com/users/7thParkk/events%7B/privacy%7D](https://api.github.com/users/7thParkk/events%7B/privacy%7D)

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