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GHSA-38m6-82c8-4xfm — parse-server

Fix: parse-community/parse-server#10463

GHSA-38m6-82c8-4xfm is a CWE-1333 vulnerability in parse-server. A fix is available for parse-server — see the affected versions and patch details below.

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

Also known asBIT-parse-2026-47138CVE-2026-47138
Published
May 23, 2026
Updated
Jun 16, 2026
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed
Exploitation data as of Sep 27, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-38m6-82c8-4xfm.

EPSS Exploitation Probability

via FIRST.org ↗
0.9%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs58th percentile — riskier than 58% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

62other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
parse-servernpm
55Kdownloads / week

Description

Impact

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.

Patches

The client SDK version capture and parsing have been removed entirely. The Parse JS SDK compatibility table defines a strict version-pinned contract between Parse Server and the Parse JS SDK; server-side adaptation to client SDK version is an obsolete pattern that contradicts that contract. The vulnerable parser, the clientSDK parameter that threaded its output through routers, and the legacy code path it gated are all removed. The X-Parse-Client-Version header and _ClientVersion JSON body field are now silently ignored on every request; supported Parse SDKs are unaffected.

Workarounds

Deploy a reverse proxy or WAF in front of Parse Server that strips or strictly size-limits the X-Parse-Client-Version header AND the _ClientVersion field in JSON request bodies on every /parse/* route before forwarding to the server. A header-size cap alone is insufficient: the body-field variant requires inspection of JSON content. Upgrading to the patched version is the recommended remediation.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
📦npmparse-server≥ 9.0.0&&< 9.9.1-alpha.19.9.1-alpha.1npm install parse-server@9.9.1-alpha.1
📦npmparse-serverall versions8.6.77npm install parse-server@8.6.77

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for parse-server, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update parse-server to 9.9.1-alpha.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-38m6-82c8-4xfm is resolved across your whole dependency graph.

  3. Workarounds

    Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### Impact 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
O3 Security · Impact-Aware SCA

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GHSA-38m6-82c8-4xfm: parse-server | O3 Security