Parse Server affected by denial-of-service via unbounded query complexity in REST and GraphQL API
Impact
An unauthenticated attacker can exhaust Parse Server resources (CPU, memory, database connections) through crafted queries that exploit the lack of complexity limits in the REST and GraphQL APIs.
All Parse Server deployments using the REST or GraphQL API are affected.
Patches
The vulnerability is fixed by introducing configurable request complexity limits via the requestComplexity server option with the following keys:
subqueryDepth: Maximum nesting depth for$inQuery,$notInQuery,$select,$dontSelectincludeDepth: Maximum depth of dot-separatedincludepathsincludeCount: Maximum number ofincludefields per querygraphQLDepth: Maximum depth of GraphQL field selectionsgraphQLFields: Maximum number of field selections in a GraphQL query
Requests using master key or maintenance key bypass these limits. Set any property to -1 to disable that specific limit.
In versions 8.6.15 and 9.5.2-alpha.2, these limits were enabled by default. This unintentionally introduced a breaking change for some applications with legitimate complex queries. In versions 8.6.46 and 9.6.0-alpha.22, the defaults were changed to -1 (disabled) to restore backwards compatibility.
The limits remain available as configuration options. To mitigate the vulnerability, upgrade to a patched version and set each requestComplexity property to a value appropriate for your application.
Workarounds
There is no known workaround.
References
- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-cmj3-wx7h-ffvg
- Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.2-alpha.2
- Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.15
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | parse-server | < 8.6.15, >= 9.0.0, < 9.5.2-alpha.2 | 8.6.15, 9.5.2-alpha.2 |
References
- https://github.com/parse-community/parse-server/security/advisories/GHSA-cmj3-wx7h-ffvg
- https://nvd.nist.gov/vuln/detail/CVE-2026-30946
- https://github.com/parse-community/parse-server
- https://github.com/parse-community/parse-server/releases/tag/8.6.15
- https://github.com/parse-community/parse-server/releases/tag/9.5.2-alpha.2
- CVSS vector
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- Weakness (CWE)
CWE-770- Platform
- npm
- Package
parse-server- Disclosed
- 11.03.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-cmj3-wx7h-ffvg - CC BY 4.0
Vulnerability history: parse-server
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 116
- First → latest
- 06.2019 06.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 17
- High 49
- Medium 40
- Low 10
Disclosures per year
- 2019: 2
- 2020: 4
- 2021: 4
- 2022: 12
- 2023: 5
- 2024: 4
- 2025: 6
- 2026: 79
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Parse Server affected by denial-of-service via unbounded query complexity in REST and GraphQL API this entry
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