How severe is CVE-2021-39187?

CVE-2021-39187 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-39187 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39187?

CVE-2021-39187 affects Parseplatform Parse-server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39187?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-39187 published?

CVE-2021-39187 was published on 2021-09-02 and last updated on 2026-06-17.

CVE-2021-39187

CVE-2021-39187 is a high-severity vulnerability in Parseplatform Parse-server with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-755.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-755
Affected product: Parseplatform Parse-server
Published: 2021-09-02
Last modified: 2026-06-17

Description

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to version 4.10.3, 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. There is a patch for this issue in version 4.10.3. No workarounds aside from upgrading are known to exist.

Frequently asked questions

What is CVE-2021-39187?: Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to version 4.10.3, 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. There is a patch for this issue in version 4.10.3. No workarounds aside from upgrading are known to exist.
How severe is CVE-2021-39187?: CVE-2021-39187 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-39187 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39187?: CVE-2021-39187 affects Parseplatform Parse-server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39187?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-39187 published?: CVE-2021-39187 was published on 2021-09-02 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:parseplatform:parse-server:*:*:*:*:*:node.js:*:*

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