parse-server has GraphQL complexity validator exponential fragment traversal DoS
Impact
The GraphQL query complexity validator can be exploited to cause a denial-of-service by sending a crafted query with binary fan-out fragment spreads. A single unauthenticated request can block the Node.js event loop for seconds, denying service to all concurrent users. This only affects deployments that have enabled the requestComplexity.graphQLDepth or requestComplexity.graphQLFields configuration options.
Patches
The fix replaces the per-branch fragment traversal with memoized fragment computation, reducing the traversal from exponential O(2^N) to linear O(N) time. Additionally, early termination aborts the traversal as soon as configured limits are exceeded.
Workarounds
Disable GraphQL complexity limits by setting requestComplexity.graphQLDepth and requestComplexity.graphQLFields to -1 (the default).
Resources
- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-mfj6-6p54-m98c
- Fix Parse Server 9: https://github.com/parse-community/parse-server/pull/10344
- Fix Parse Server 8: https://github.com/parse-community/parse-server/pull/10345
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | parse-server | >= 9.0.0, < 9.7.0-alpha.12, < 8.6.68 | 9.7.0-alpha.12, 8.6.68 |
References
- https://github.com/parse-community/parse-server/security/advisories/GHSA-mfj6-6p54-m98c
- https://nvd.nist.gov/vuln/detail/CVE-2026-34573
- https://github.com/parse-community/parse-server/pull/10344
- https://github.com/parse-community/parse-server/pull/10345
- https://github.com/parse-community/parse-server/commit/ea15412795f34594cc8a674fe858d445675e0295
- https://github.com/parse-community/parse-server/commit/f759bda075298ec44e2b4fb57659a0c56620483b
- https://github.com/parse-community/parse-server
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N- Weakness (CWE)
CWE-407- Platform
- npm
- Package
parse-server- Disclosed
- 31.03.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-mfj6-6p54-m98c - 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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