CVE-2026-34573Public exploitNetwork attack vector

Service hang via exponential GraphQL fragment traversal

Published Mar 31, 2026 · Updated Mar 31, 2026

Algorithmic complexity in Parse Server before 8.6.68 and 9.0.0 through 9.7.0-alpha.11 allows remote attackers to hang the service. The GraphQL query complexity validator recursively traverses each branch of binary fan-out fragment spreads without memoizing shared fragments, causing exponential work on one crafted query. The unauthenticated request blocks the Node.js event loop and denies service to concurrent users only when requestComplexity.graphQLDepth or requestComplexity.graphQLFields is enabled.

CVSS severity8.2
High
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Algorithmic complexity in Parse Server before 8.6.68 and 9.0.0 through 9.7.0-alpha.11 allows remote attackers to hang the service. The GraphQL query complexity validator recursively traverses each branch of binary fan-out fragment spreads without memoizing shared fragments, causing exponential work on one crafted query. The unauthenticated request blocks the Node.js event loop and denies service to concurrent users only when requestComplexity.graphQLDepth or requestComplexity.graphQLFields is enabled.

The record

CVE
CVE-2026-34573
Published
Mar 31, 2026
Updated
Mar 31, 2026
Vendor
Parse Platform
Product
Parse Server
Classifications
CWE-407, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 8.6.68
  2. Affected versionversion=>= 9.0.0, < 9.7.0-alpha.12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Parse Platform · Parse Serverversion=< 8.6.68; version=>= 9.0.0, < 9.7.0-alpha.12

Published CVSS scores

8.2GitHub, Inc.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
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-407Inefficient Algorithmic Complexity
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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