Security readout for executives and security teams
Plain-English summary
Parse Server versions before 4.10.3 can crash when handling an invalid query option, causing service disruption. The issue affects availability, not confidentiality or integrity, based on the CVSS vector. Public sources identify version 4.10.3 as the patched release and state no workaround is known besides upgrading.
Executive priority
High priority for organizations using Parse Server, because unauthenticated network traffic can cause downtime in affected versions. The fix path is clear: upgrade. Prioritize systems supporting customer-facing apps or critical business workflows.
Technical view
CVE-2021-39187 is a network-reachable denial-of-service flaw in parse-community Parse Server before 4.10.3. An invalid value for the query `explain` option triggers a MongoDB Node.js driver exception that affected Parse Server versions cannot catch, terminating the server process.
Likely exposure
Exposure is most likely where Parse Server versions earlier than 4.10.3 are deployed and reachable by clients over the network, especially public API backends. The bundle does not identify affected CPEs or downstream packaged products.
Exploitation context
The CVSS vector indicates network access, low attack complexity, no privileges, and no user interaction. CISA KEV is false in the supplied bundle, and no cited source states active exploitation. Treat this as a plausible unauthenticated availability risk, not confirmed exploitation.
Researcher notes
The advisory ties the crash to invalid `explain` option handling and an uncaught MongoDB Node.js driver exception. Sources do not provide evidence of data exposure, code execution, or active exploitation. Keep validation non-destructive and focused on version and exposure checks.
Mitigation direction
- Upgrade Parse Server to version 4.10.3 or later.
- Prioritize internet-facing and business-critical Parse Server deployments.
- Check Parse Server vendor guidance for any newer upgrade recommendations.
- Monitor affected services for crash loops or abnormal restarts.
- Review dependency management to prevent reintroducing vulnerable Parse Server versions.
Validation and detection
- Inventory all Parse Server deployments and record their running versions.
- Confirm no production or staging instance runs Parse Server below 4.10.3.
- Review API exposure for Parse Server endpoints reachable from untrusted networks.
- Check service logs for unexplained crashes around query processing.
- Run normal application regression tests after upgrading.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-74: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-39187 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/parse-community/parse-server/security/advisories/GHSA-xqp8-w826-hh6xCVE reference · x_refsource_CONFIRM
- https://github.com/parse-community/parse-server/commit/308668c89474223e2448be92d6823b52c1c313ecCVE reference · x_refsource_MISC
- https://github.com/parse-community/parse-server/releases/tag/4.10.3CVE reference · x_refsource_MISC
- https://jira.mongodb.org/browse/NODE-3463CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.