Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.77 and 9.9.1-alpha.1, an unauthenticated attacker who knows a publicly-known Parse Application ID can submit a single HTTP request whose client SDK version field contains adversarial input that triggers polynomial backtracking in a request-header parser. The parsing runs before session authentication and before rate limiting on every /parse/* request, so the request consumes seconds to minutes of synchronous CPU on a Node.js worker before any access control evaluates it. A small number of concurrent requests can saturate a worker; a single large request via the body-field variant can pin a worker for minutes. Production deployments running the default configuration are affected. This issue has been patched in versions 8.6.77 and 9.9.1-alpha.1.

Project Subscriptions

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-38m6-82c8-4xfm Parse Server: Pre-authentication denial of service via client version header regex backtracking
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 12 Jun 2026 19:45:00 +0000

Type Values Removed Values Added
First Time appeared Parse Community
Parse Community parse Server
Vendors & Products Parse Community
Parse Community parse Server

Fri, 12 Jun 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 12 Jun 2026 18:45:00 +0000

Type Values Removed Values Added
Description Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.77 and 9.9.1-alpha.1, an unauthenticated attacker who knows a publicly-known Parse Application ID can submit a single HTTP request whose client SDK version field contains adversarial input that triggers polynomial backtracking in a request-header parser. The parsing runs before session authentication and before rate limiting on every /parse/* request, so the request consumes seconds to minutes of synchronous CPU on a Node.js worker before any access control evaluates it. A small number of concurrent requests can saturate a worker; a single large request via the body-field variant can pin a worker for minutes. Production deployments running the default configuration are affected. This issue has been patched in versions 8.6.77 and 9.9.1-alpha.1.
Title Parse Server: Pre-authentication denial of service via client version header regex backtracking
Weaknesses CWE-1333
References
Metrics cvssV4_0

{'score': 8.7, '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'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-12T18:56:14.419Z

Reserved: 2026-05-18T19:50:18.696Z

Link: CVE-2026-47138

cve-icon Vulnrichment

Updated: 2026-06-12T18:56:11.468Z

cve-icon NVD

Status : Received

Published: 2026-06-12T19:16:28.257

Modified: 2026-06-12T19:16:28.257

Link: CVE-2026-47138

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-12T19:30:31Z

Weaknesses