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SQLFluff: Recursive Stack Overflow in Parser

High severity GitHub Reviewed Published May 14, 2026 in sqlfluff/sqlfluff • Updated Jul 6, 2026

Package

pip sqlfluff (pip)

Affected versions

< 4.1.0

Patched versions

4.1.0

Description

Impact

In deployments where untrusted users can provide SQL queries to be linted, an untrusted user can submit a malicious query with deliberate excessive nesting to any application using the parser to trigger a Denial of Service through resource exhaustion.

Patches

Versions 4.1.0 and up contain a configurable recursion limit, which is enabled by default, to prevent this manner of exploit.

Credit

Ori Nakar from Imperva Threat Research Team.

References

@alanmcruickshank alanmcruickshank published to sqlfluff/sqlfluff May 14, 2026
Published to the GitHub Advisory Database May 19, 2026
Reviewed May 19, 2026
Published by the National Vulnerability Database Jun 9, 2026
Last updated Jul 6, 2026

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(18th percentile)

Weaknesses

Uncontrolled Recursion

The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack. Learn more on MITRE.

CVE ID

CVE-2026-46373

GHSA ID

GHSA-wmhf-fqc8-vxhh

Source code

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