CVE-2026-61448
LowCVSS 2.1Exploitation Probability (EPSS)
Low risk16th percentile - higher than 16% of all known CVEs
Summary
Parse Server versions >= 9.0.0, < 9.10.0-alpha.2 and <= 8.6.83 are affected by a stored XSS vulnerability. A malformed Content-Type (e.g., 'image//svg+xml') bypasses the file extension blocklist and is stored unchanged; on storage adapters like S3, GCS, or Azure, browsers fall back to MIME-sniffing and render HTML content, executing embedded scripts.
Risk Assessment
An attacker can upload a file with malicious JavaScript that executes in the application's origin when other users open the file URL, leading to session theft, data leakage, or actions performed on behalf of the victim.
Recommendation
Upgrade Parse Server to version 9.10.0-alpha.2 or 8.6.84 immediately. If upgrade is not possible, temporarily disable storage adapters that preserve Content-Type (S3, GCS, Azure) or deploy WAF rules to block malformed Content-Type headers.
Original NVD description (English source)
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.