Stored XSS via trailing-dot upload blocklist bypass
Published Jun 12, 2026 · Updated Jun 12, 2026
Stored XSS in Parse Server allows remote authenticated users to execute script by uploading a dangerous file with a trailing-dot name. File upload validation treats the empty extension after a final dot as allowed and forwards the supplied Content-Type to the storage adapter. Exploitation requires an adapter such as S3 or GCS that serves that type and a victim to open the file URL; default GridFS is unaffected.
Summary
What happened
Stored XSS in Parse Server allows remote authenticated users to execute script by uploading a dangerous file with a trailing-dot name. File upload validation treats the empty extension after a final dot as allowed and forwards the supplied Content-Type to the storage adapter. Exploitation requires an adapter such as S3 or GCS that serves that type and a victim to open the file URL; default GridFS is unaffected.
The record
- CVE
- CVE-2026-53724
- Published
- Jun 12, 2026
- Updated
- Jun 12, 2026
- Vendor
- Parse Platform
- Product
- Parse Server
- Classifications
- CWE-434, T1189
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 12, 2026CVE publishedPublication date reported by the CVE source.
- Jun 12, 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=< 8.6.79
- Affected versionversion=>= 9.0.0, < 9.9.1-alpha.4
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
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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