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CVE-2026-33704· NVD / CVE Program· CNA GitHub_M

Chamilo LMS Affected by Authenticated Arbitrary File Write via BigUpload endpoint

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.

HighCVSS 8.8 · v3.1—No exploit Fix available
Published
Apr 10, 2026
Updated
Jun 17, 2026
EPSS
0.8% · 53th percentile
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Report tools

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Action score

35

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
8.8
CNA · GitHub_M
7.1
1.7 point gap

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
chamilochamilo lms

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • chamilo chamilo lmsbefore 1.11.38

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • chamilo chamilo-lms

    • < 1.11.38affected

Same product

chamilo: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-4220Chamilo LMS Unauthenticated Big Upload File Remote Code Execution
    47Plan
  • CVE-2021-35414Chamilo LMS v1.11.x was discovered to contain a SQL injection via the doc parameter in main/plagiarism/compilatio/upload.php.
    40Plan
  • CVE-2019-13082Chamilo LMS 1.11.8 and 2.x allows remote code execution through an lp_upload.php unauthenticated file upload feature.
    40Plan
  • CVE-2018-1999019Chamilo LMS version 11.x contains an Unserialization vulnerability in the "hash" GET parameter for the api endpoint located at /webservices/
    40Plan
  • CVE-2026-33707Weak Password Recovery Mechanism for Forgotten Password in chamilo/chamilo-lms
    39Monitor
  • CVE-2025-50187Chamilo: Evaluation of untrusted user input leads to Remote Code Execution
    39Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
chamilo chamilo-lms1.11.38 · descriptionVendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-329310 days apartChamilo LMS has Arbitrary File Upload via MIME-Only Validation in Exercise Sound Upload Leads to RCE
    35Monitor
  • CVE-2026-2904135 days apartChamilo: Authenticated Remote Code Execution via Unrestricted File Upload
    35Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

  • CVE-2026-341604 days apartChamilo LMS: Unauthenticated SSRF via PENS Plugin allows attacker to probe internal network and reach cloud metadata services
    34Monitor

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-434 · Unrestricted Upload of File with Dangerous Type

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Noroxi analysis

No Noroxi analysis for this record yet

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Change log

  1. Fix✗ → ✓

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References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records