Authenticated code execution via GIF-header MIME bypass
Published Aug 21, 2023 · Updated Jul 9, 2026
Unrestricted file upload in BoidCMS 2.0.0 allows remote authenticated users to execute arbitrary PHP code through the media uploader. The uploader trusts finfo's MIME result, so a PHP file prefixed with GIF89a is classified as an image and retained with its executable .php extension. An authenticated account with upload access is required; requesting the uploaded file then runs its PHP payload with the web server's privileges.
Summary
What happened
Unrestricted file upload in BoidCMS 2.0.0 allows remote authenticated users to execute arbitrary PHP code through the media uploader. The uploader trusts finfo's MIME result, so a PHP file prefixed with GIF89a is classified as an image and retained with its executable .php extension. An authenticated account with upload access is required; requesting the uploaded file then runs its PHP payload with the web server's privileges.
The record
- CVE
- CVE-2023-38836
- Published
- Aug 21, 2023
- Updated
- Jul 9, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-434, T1505.003
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 21, 2023CVE publishedPublication date reported by the CVE source.
- Jul 9, 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?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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
- CVE-2023-38836 PoC exploitproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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