CVE-2026-34602: Chamilo LMS: IDOR in /api/course_rel_users Allows Unauthorized Enrollment of Arbitrary Users into Courses
Noroxi assessment
Priority: Monitor (action score 28/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.20% (FIRST EPSS).
- 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.
- No fixed version is recorded, but the references include a patch (commit or PR) link.
Low priority for now. See the fix and affected versions sections below.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
Chamilo LMS is an open-source learning management system. In versions prior to 2.0.0-RC.3, the /api/course_rel_users endpoint is vulnerable to Insecure Direct Object Reference (IDOR), allowing an authenticated attacker to modify the user parameter in the request body to enroll any arbitrary user into any course without proper authorization checks. The backend trusts the user-supplied input for the user field and performs no server-side verification that the requester owns the referenced user ID or has permission to act on behalf of other users. This enables unauthorized manipulation of user-course relationships, potentially granting unintended access to course materials, bypassing enrollment controls, and compromising platform integrity. This issue has been fixed in version 2.0.0-RC.3.
- Published
- Apr 14, 2026
- Updated
- Jul 24, 2026
- EPSS
- 0.2% · 10th percentile
- CWE
- CWE-639
Report tools
Action score
28
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 7.1
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- No fixed version yet
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| chamilo | chamilo lms | cpe:2.3:a:chamilo:chamilo_lms |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- chamilo chamilo lmsup to 1.11.38 inclusive
- chamilo chamilo lms2.0.0
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
- < 2.0.0-RC.3affected
Same product
chamilo: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-4220Chamilo LMS Unauthenticated Big Upload File Remote Code Execution60This week
- 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
Published before and after this one in the same product
- ← EarlierCVE-2026-34161Apr 14, 2026 · Chamilo LMS: Stored XSS via Malicious File Upload in Social Post Attachments Leads to Arbitrary JavaScript Execution20Monitor
- ← EarlierCVE-2026-34370Apr 14, 2026 · Chamilo LMS: IDOR in the Notebook Module allows an attacker to view other users' private notes26Monitor
- Later →CVE-2026-35196Apr 14, 2026 · Chamilo LMS has OS Command Injection via export_all_certificates action36Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
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.
No history yet (it accumulates with the daily EPSS job).
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 researchersFinders, 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-2026-329304 days apartChamilo LMS has an IDOR in Gradebook Allows Cross-Course Evaluation Edit Without Ownership Check28Monitor
- CVE-2026-337024 days apartChamilo LMS has an Insecure Direct Object Reference (IDOR)28Monitor
- CVE-2026-337034 days apartChamilo LMS Critical IDOR: Any Authenticated User Can Extract All Users’ Personal Data and API Tokens28Monitor
- CVE-2026-331414 days apartChamilo LMS has an IDOR in REST API Stats Endpoint Exposes Any User's Learning Data26Monitor
- CVE-2026-337364 days apartChamilo LMS has an Insecure Direct Object Reference (IDOR) - User Data Exposure26Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
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
- low · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-639 · Authorization Bypass Through User-Controlled KeyCVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
nvd-secondary
Root cause
The endpoint fetches the record by the ID sent in the request, but never checks whether the record belongs to the requesting user.
The bug in code
The whole CWE-639 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
const invoice = await Invoice.findById(req.params.id);
res.json(invoice);Fixed
const invoice = await Invoice.findOne({
id: req.params.id,
ownerId: req.user.id,
});
if (!invoice) return res.sendStatus(404);
res.json(invoice);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Show all references (4 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.