High severity · published Apr 10, 2026
CVE-2026-33704
Chamilo LMS Affected by Authenticated Arbitrary File Write via BigUpload endpoint
8.8
CVSS
0.4%
EPSS
No
On KEV
Description
Chamilo LMS is a learning management system. Prior to 1.11.38, any authenticated user (including students) can write arbitrary content to files on the server via the BigUpload endpoint. The key parameter controls the filename and the raw POST body becomes the file content. While .php extensions are filtered to .phps, the .pht extension passes through unmodified. On Apache configurations where .pht is handled as PHP, this leads to Remote Code Execution. This vulnerability is fixed in 1.11.38.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CH
chamilo-lms · chamilo
< 1.11.38 · source: vendor
CL
Chamilo Lms · Chamilo
before 1.11.38 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33704
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33704
Patch
https://github.com/chamilo/chamilo-lms/commit/9748f1ffbdb8b6dc84c0e0591c9d3c1d92e21c00
Vendor Advisory
https://github.com/chamilo/chamilo-lms/security/advisories/GHSA-phfx-pwwg-945v
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