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PatchSiren cyber security CVE debrief

CVE-2026-34573 parse-community CVE debrief

CVE-2026-34573 is a high-severity vulnerability in Parse Server, an open-source backend, that can be exploited to cause a denial-of-service via a crafted GraphQL query with binary fan-out fragment spreads. This issue affects deployments with enabled requestComplexity.graphQLDepth or requestComplexity.graphQLFields configuration options. A single unauthenticated request can block the Node.js event loop for seconds, denying service to all concurrent users. The vulnerability has been patched in versions 8.6.68 and 9.7.0-alpha.12.

Vendor
parse-community
Product
parse-server
CVSS
HIGH 8.2
CISA KEV
Not listed in stored evidence
Original CVE published
2026-03-31
Original CVE updated
2026-07-24
Advisory published
2026-03-31
Advisory updated
2026-07-24

Who should care

Users of Parse Server, especially those who have enabled the requestComplexity.graphQLDepth or requestComplexity.graphQLFields configuration options, should be aware of this vulnerability and take immediate action to patch their deployments. This includes reviewing and adjusting GraphQL query complexity configuration options and monitoring for suspicious GraphQL queries.

Technical summary

The GraphQL query complexity validator in Parse Server can be exploited to cause a denial-of-service by sending a crafted query with binary fan-out fragment spreads. This issue has been patched in versions 8.6.68 and 9.7.0-alpha.12. The vulnerability has a CVSS score of 8.2 and is considered high severity. A single unauthenticated request can block the Node.js event loop for seconds, denying service to all concurrent users.

Defensive priority

High

Recommended defensive actions

  • Apply patches or updates to vulnerable versions of Parse Server
  • Review and adjust GraphQL query complexity configuration options
  • Monitor for suspicious GraphQL queries
  • Implement compensating controls to mitigate potential impact
  • Review affected deployments and assign an owner for follow-up
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record was published on 2026-03-31T16:16:33.737Z and last modified on 2026-07-24T20:10:00.147Z. The NVD entry is currently Analyzed. Evidence is limited to public sources and may not reflect the full scope or impact of this vulnerability. Defenders should verify affected deployments and review official advisories for specific guidance.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-34573 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-34573

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-34573 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-34573

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.