Vulnerability details

CVE-2026-47138

parse-community parse-server

Parse Server: Pre-authentication denial of service via client version header regex backtracking

CVSS 4.0
8.7High

Official 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.

CVSS scores

ScoreVersionSourceVector
8.7High 4.0 CVEProject cvelistV5 (CNA) (GitHub_M) 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

Affected products

VendorProductVersionsSource
parse-community parse-server < 8.6.77 CVEProject cvelistV5 (CNA)
parse-community parse-server >= 9.0.0, < 9.9.1-alpha.1 CVEProject cvelistV5 (CNA)

References and advisories

3
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Details

Published
2026-06-12
Last updated
2026-06-12
State
Published
Assigner (CNA)
GitHub_M

Exploit prediction (EPSS)

0.58%
Probability of exploitation in 30 days
48.1%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
Yes
Exploitation
None
Technical impact
Partial

Weaknesses (CWE)

  • CWE-1333
    Inefficient Regular Expression Complexity