Authenticated arbitrary file upload via extension parser bypass
Published Dec 22, 2025 · Updated Dec 22, 2025
Unrestricted file upload in liweiyi ChestnutCMS 1.5.0 through 1.5.8 allows remote authenticated users to upload arbitrary file types. The /dev-api/common/upload endpoint treats text following wx_fmt= in specially formed filenames as the extension, so an allowed txt value masks the file's actual type. A valid session or token is required; the proof demonstrates arbitrary-type file storage and limited empty-directory creation, not code execution.
Summary
What happened
Unrestricted file upload in liweiyi ChestnutCMS 1.5.0 through 1.5.8 allows remote authenticated users to upload arbitrary file types. The /dev-api/common/upload endpoint treats text following wx_fmt= in specially formed filenames as the extension, so an allowed txt value masks the file's actual type. A valid session or token is required; the proof demonstrates arbitrary-type file storage and limited empty-directory creation, not code execution.
The record
- CVE
- CVE-2025-15009
- Published
- Dec 22, 2025
- Updated
- Dec 22, 2025
- Vendor
- Liweiyi
- Product
- ChestnutCMS
- Classifications
- CWE-284, CWE-434, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Dec 22, 2025CVE publishedPublication date reported by the CVE source.
- Dec 22, 2025Record 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=1.5.0
- Affected versionversion=1.5.1
- Affected versionversion=1.5.2
- Affected versionversion=1.5.3
- Affected versionversion=1.5.4
- Affected versionversion=1.5.5
- Affected versionversion=1.5.6
- Affected versionversion=1.5.7
- Affected versionversion=1.5.8
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
- ChestnutCMS Arbitrary File Upload proofproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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