sqlparse: TokenList.__init__ materializes O(subtree) value per group, causing CPU DoS before depth/token caps trigger

Exploitation

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

CVSS 4.0

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

EPSS

• CVE-2026-54284: 0.33% estimated exploitation activity in the next 30 days; percentile 26.50 (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 sqlparse ships hard limits (MAXGROUPINGDEPTH=100, MAXGROUPINGTOKENS=10000) intended to bound parsing work on attacker-supplied SQL, but the path that reaches those limits is itself O(ndepth) per token-group construction. A ~1-2 KB SQL payload (e.g. SELECT (((((1))))) ... with 500-2000 nesting levels, or a 200-400-level nested CASE WHEN chain) drives the parser to spend multiple seconds of CPU before the depth cap raises SQLParseError. Concretely: a 2 KB malicious payload consumes ~10 seconds of CPU per request on a single worker (~5000x CPU-to-input amplification), while a benign 1 KB SQL completes in ~3 ms. The root cause is TokenList.init calling super().init(None, str(self)). TokenList.str flattens the entire subtree on every call, and grouping constructs a new TokenList for every parenthesis / CASE / list group, so a tree of depth d with n total tokens performs O(nd) flatten work just to materialize the cached value field, which is then never read for grouped nodes (they…

Published by the source

17 Aug 2026, 17:49 UTC

Last modified by the source

17 Aug 2026, 17:49 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-pwgv-4x5q-6m9f

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# Patch Next advisory brief: CVE-2026-54284

Advisory: sqlparse: TokenList.__init__ materializes O(subtree) value per group, causing CPU DoS before depth/token caps trigger
IDs: CVE-2026-54284, GHSA-pwgv-4x5q-6m9f
Record: https://patchnext.com/advisories/cve-2026-54284 (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
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-pwgv-4x5q-6m9f (GitHub-reviewed advisory GHSA-pwgv-4x5q-6m9f lists affected ranges: PyPI sqlparse >=0 <=0.5.5)

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