Stored XSS via malformed Content-Type bypass
Published Jul 11, 2026 · Updated Jul 11, 2026
Stored XSS in Parse Server before 8.6.84 and 9.0.0 through 9.10.0-alpha.1 allows remote authenticated users to execute script via file uploads. When mime cannot recognize an extension, the upload handler stores an unvalidated client Content-Type, so malformed media types evade the extension blocklist. Exploitation requires upload access, a storage adapter that preserves the header, and another user opening the file URL; default GridFS is unaffected.
Summary
What happened
Stored XSS in Parse Server before 8.6.84 and 9.0.0 through 9.10.0-alpha.1 allows remote authenticated users to execute script via file uploads. When mime cannot recognize an extension, the upload handler stores an unvalidated client Content-Type, so malformed media types evade the extension blocklist. Exploitation requires upload access, a storage adapter that preserves the header, and another user opening the file URL; default GridFS is unaffected.
The record
- CVE
- CVE-2026-61448
- Published
- Jul 11, 2026
- Updated
- Jul 11, 2026
- Vendor
- Parse Platform
- Product
- Parse Server
- Classifications
- CWE-434, T1203
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 11, 2026CVE publishedPublication date reported by the CVE source.
- Jul 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <8.6.84
- Affected versionversion=9.0.0 <9.10.0-alpha.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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