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CVE-2026-53724 parse-community CVE debrief

CVE-2026-53724 is a low-severity vulnerability in Parse Server, an open-source backend. The issue allows an attacker to bypass the default file upload extension blocklist by appending a trailing dot to a filename whose extension would otherwise be blocked. This can lead to stored XSS when a victim opens the file URL. The vulnerability has been patched in versions 8.6.79 and 9.9.1-alpha.4.

Vendor
parse-community
Product
parse-server
CVSS
LOW 2.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-12
Original CVE updated
2026-06-15
Advisory published
2026-06-12
Advisory updated
2026-06-15

Who should care

Users of Parse Server, especially those hosting it on their own infrastructure, should be aware of this vulnerability and take steps to update to a patched version.

Technical summary

The vulnerability exists in the file upload handling of Parse Server. By appending a trailing dot to a filename with a blocked extension, an attacker can bypass the blocklist check. This causes the extension parser to extract an empty string, short-circuiting the blocklist check. The attacker-controlled Content-Type is then forwarded to the storage adapter unchanged. Storage adapters that persist and serve the provided Content-Type, such as S3 or GCS, serve the file with an active type like image/svg+xml, enabling stored XSS.

Defensive priority

Low

Recommended defensive actions

  • Update Parse Server to version 8.6.79 or 9.9.1-alpha.4 or later.
  • Review file upload handling and Content-Type headers in your implementation.

Evidence notes

The vulnerability was patched in versions 8.6.79 and 9.9.1-alpha.4. The default GridFS adapter is not affected as it sets X-Content-Type-Options: nosniff on responses.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-53724 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-53724

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-53724 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-53724

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.