sqlparse: Reindentation of tuple lists causes near-cap quadratic CPU consumption

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.1 · CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-84305: 0.19% estimated exploitation activity in the next 30 days; percentile 8.60 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary When SQL is formatted with reindentation enabled, ReindentFilter repeatedly rebuilds prefixes of the current statement to calculate token offsets. An attacker who controls SQL sent to this opt-in formatting path can supply a parenthesized tuple list that remains just below the grouping-token cap. Thousands of offset calculations then traverse an expanding token tree, causing multi-second CPU consumption from an input of roughly 16 KB and degrading service availability. Details ReindentFilter.getoffset() joins the tokens returned by flattenuptotoken() to calculate the current output position. Each call begins by flattening the current statement from its start and walks until the target token. Tuple-list reindentation invokes this calculation repeatedly as it processes many parenthesized values, so later calls redo an increasingly large amount of prior work. The vulnerable path is reached through sqlparse.format(sql, reindent=True) and sqlformat --reindent. A carefully sized…

Published by the source

1 Sep 2026, 21:20 UTC

Last modified by the source

1 Sep 2026, 21:21 UTC

Source last checked

26 Oct 2026, 13:51 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-cfqr-cjx5-5jcm

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# Patch Next advisory brief: CVE-2026-84305

Advisory: sqlparse: Reindentation of tuple lists causes near-cap quadratic CPU consumption
IDs: CVE-2026-84305, GHSA-cfqr-cjx5-5jcm
Record: https://patchnext.com/advisories/cve-2026-84305 (revision 1, source checked 26 Oct 2026, 13:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: sqlparse 0.6.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI sqlparse: affected <= 0.5.5; fixed in 0.6.0

## Suggested inspection (read-only)
- `python -m pip show sqlparse`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on sqlparse.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-cfqr-cjx5-5jcm (GitHub-reviewed advisory GHSA-cfqr-cjx5-5jcm lists affected ranges: PyPI sqlparse >=0 <=0.5.5)

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