How severe is GHSA-r899-h629-j84r?

No CVSS score has been assigned to GHSA-r899-h629-j84r yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-r899-h629-j84r?

Affected package information for GHSA-r899-h629-j84r is not yet fully mapped. Check the official advisory links for details.

How do I fix GHSA-r899-h629-j84r?

Upgrade the affected component to the fixed release for GHSA-r899-h629-j84r, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.

How do I detect GHSA-r899-h629-j84r in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate GHSA-r899-h629-j84r if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is GHSA-r899-h629-j84r actively exploited in the wild?

No public exploit code has been indexed for GHSA-r899-h629-j84r yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-r899-h629-j84r?

GHSA-r899-h629-j84r has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 36th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-r899-h629-j84r?

GHSA-r899-h629-j84r is classified as Unrestricted File Upload (CWE-434). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-r899-h629-j84r published, and has it been updated?

GHSA-r899-h629-j84r was published on July 11, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

Parse Server 9.0.0 Stored XSS via malformed Content-Type

Exploitation Status

No confirmed exploitation observed yet

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-r899-h629-j84r.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs36th percentile — riskier than 36% of all scored CVEsHighest risk

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

Description

Parse Server is affected by a stored cross-site scripting (XSS) vulnerability in versions >= 9.0.0, < 9.10.0-alpha.2 and <= 8.6.83. When an uploaded file's extension is not recognized by the mime package, Parse Server preserves the client-supplied Content-Type. A malformed Content-Type that is not a valid type/subtype media type (e.g., 'image', 'image/', or 'image//svg+xml') bypasses the fileUpload.fileExtensions blocklist and is stored unchanged. On storage adapters that persist and serve the uploaded Content-Type (such as Amazon S3, Google Cloud Storage, or Azure Blob Storage), a browser cannot parse the malformed value and falls back to MIME-sniffing; a file whose body begins with HTML is rendered as HTML, executing embedded script in the application's origin against other users who open the file URL. The default GridFS storage adapter is not affected. Fixed in 9.10.0-alpha.2 and 8.6.84.

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Fix
Upgrade the affected component to the fixed release for GHSA-r899-h629-j84r, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

Parse Server is affected by a stored cross-site scripting (XSS) vulnerability in versions >= 9.0.0, < 9.10.0-alpha.2 and <= 8.6.83. When an uploaded file's extension is not recognized by the mime package, Parse Server preserves the client-supplied Content-Type. A malformed Content-Type that is not a valid type/subtype media type (e.g., 'image', 'image/', or 'image//svg+xml') bypasses the fileUpload.fileExtensions blocklist and is stored unchanged. On storage adapters that persist and serve the uploaded Content-Type (such as Amazon S3, Google Cloud Storage, or Azure Blob Storage), a browser can

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Parse Server 9.0.0 Stored XSS via malformed Content-TypeGHSA-r899-h629-j84r