High
Parse Server: GraphQL complexity validator exponential fragment traversal DoS
Type: advisorySources: OSV
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.68 and 9.7.0-alpha.12, 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. This issue has been patched in versions 8.6.68 and 9.7.0-alpha.12.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-34573
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 7 Nov 2026, 11:52 UTC · Revision 1
Source evidence
Parse Server: GraphQL complexity validator exponential fragment traversal DoS
core-osv · Original sourcePublished 31 Mar 2026, 15:06 UTC
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.68 and 9.7.0-alpha.12, 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. This issue has been patched in versions 8.6.68 and 9.7.0-alpha.12.
osv:CVE-2026-34573
Complete source record
{
"id": "4c5d38a3fa4f41cee2d64f06596072a3a01774b3e61a7d1a489fb35851e9ca92",
"url": "https://osv.dev/vulnerability/CVE-2026-34573",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Parse Server: GraphQL complexity validator exponential fragment traversal DoS",
"summary": "Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.68 and 9.7.0-alpha.12, 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. This issue has been patched in versions 8.6.68 and 9.7.0-alpha.12.",
"evidence": "osv:CVE-2026-34573",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2026-34573",
"aliases": [
"BIT-parse-2026-34573",
"CVE-2026-34573",
"GHSA-mfj6-6p54-m98c"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "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"
}
],
"affected": [
{
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"database_specific": {
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}
}
],
"modified": "2026-10-28T02:30:50.977502727Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34573.json",
"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/commit/ea15412795f34594cc8a674fe858d445675e0295",
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],
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}
},
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{
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"evidence": "/id"
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"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 519195,
"published_at": "2026-03-31T15:06:33.372+00:00"
}