Parse Server crashes with query parameter

Answer in brief

CVE-2021-39187 records a High severity (CVSS 7.5) vulnerability in Parse Server crashes with query parameter. The current sources do not mark it as known exploited. The current feed maps parse-server (npm). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 2, 2021Updated Sep 10, 2026Source checked Sep 10, 2026First seen by HOL Aug 7, 2026Material review Sep 10, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.5
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps parse-server (npm). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
parse-servernpm	>=0 <4.10.3	4.10.3

Recommended response

Check inventory. Check lockfiles and deployed manifests for parse-server.
Review the reported fix. Update parse-server to 4.10.3 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 2, 2021
Evidence: source:osv:source_dates:source-dates:record
Source modified
Sep 10, 2026
Evidence: source:osv:source_dates:source-dates:record
First seen by HOL
Aug 7, 2026

Sources and claim methodology

Upstream source description

### Impact Parse Server crashes when if a query request contains an invalid value for the `explain` option. This is due to a bug in the MongoDB Node.js driver which throws an exception that Parse Server cannot catch. ### Patches Upgrade to Parse Server 4.10.3

Quoted source text, attributed separately from HOL analysis.