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TI-2026-26461 Aliases CVE-2026-34161

Chamilo LMS: Stored XSS via Malicious File Upload in Social Post Attachments Leads to Arbitrary JavaScript Execution

Priority LOW 23CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

Chamilo LMS is an open-source learning management system. In versions prior to 2.0.0-RC.3, a Stored Cross-Site Scripting (XSS) vulnerability exists in the social post attachment upload functionality, where an authenticated user can upload a malicious HTML file containing JavaScript via the /api/social_post_attachments endpoint. The uploaded file is served back from the application at the generated contentUrl without sanitization, content type restrictions, or a Content-Disposition: attachment header, causing the JavaScript to execute in the browser within the application's origin. Because the payload is stored server-side and runs in the trusted origin, an attacker can perform session hijacking, account takeover, privilege escalation (if an admin views the link), and arbitrary actions on behalf of the victim. This issue has been fixed in version 2.0.0-RC.3.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00219 12th percentileScored 2026-11-07
Fix Fixed chamilo-lms (chamilo): 2.0.0-RC.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
chamilochamilo-lmsbefore 2.0.0-RC.32.0.0-RC.3Patch availableCNA
  • chamilo-lms Vendorchamilo Affected before 2.0.0-RC.3 Fixed in 2.0.0-RC.3 Patch available CNA

CPE configurations NVD · 11

CPEVersionsRoleVendor
cpe:2.3:a:chamilo:chamilo_lms:*:*:*:*:*:*:*:*up to 1.11.38Vulnerablechamilo
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha1:*:*:*:*:*:*2.0.0 alpha1Vulnerablechamilo
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha2:*:*:*:*:*:*2.0.0 alpha2Vulnerablechamilo
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha3:*:*:*:*:*:*2.0.0 alpha3Vulnerablechamilo
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha4:*:*:*:*:*:*2.0.0 alpha4Vulnerablechamilo
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha5:*:*:*:*:*:*2.0.0 alpha5Vulnerablechamilo
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta1:*:*:*:*:*:*2.0.0 beta1Vulnerablechamilo
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta2:*:*:*:*:*:*2.0.0 beta2Vulnerablechamilo
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta3:*:*:*:*:*:*2.0.0 beta3Vulnerablechamilo
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:rc1:*:*:*:*:*:*2.0.0 rc1Vulnerablechamilo
  • cpe:2.3:a:chamilo:chamilo_lms:*:*:*:*:*:*:*:* Versions up to 1.11.38 Vulnerable ·chamilo
  • cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha1:*:*:*:*:*:* Versions 2.0.0 alpha1 Vulnerable ·chamilo
  • cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha2:*:*:*:*:*:* Versions 2.0.0 alpha2 Vulnerable ·chamilo
  • cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha3:*:*:*:*:*:* Versions 2.0.0 alpha3 Vulnerable ·chamilo
  • cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha4:*:*:*:*:*:* Versions 2.0.0 alpha4 Vulnerable ·chamilo
  • cpe:2.3:a:chamilo:chamilo_lms:2.0.0:alpha5:*:*:*:*:*:* Versions 2.0.0 alpha5 Vulnerable ·chamilo
  • cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta1:*:*:*:*:*:* Versions 2.0.0 beta1 Vulnerable ·chamilo
  • cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta2:*:*:*:*:*:* Versions 2.0.0 beta2 Vulnerable ·chamilo
  • cpe:2.3:a:chamilo:chamilo_lms:2.0.0:beta3:*:*:*:*:*:* Versions 2.0.0 beta3 Vulnerable ·chamilo
  • cpe:2.3:a:chamilo:chamilo_lms:2.0.0:rc1:*:*:*:*:*:* Versions 2.0.0 rc1 Vulnerable ·chamilo
Show 1 more CPE
CPEVersionsRoleVendor
cpe:2.3:a:chamilo:chamilo_lms:2.0.0:rc2:*:*:*:*:*:*2.0.0 rc2Vulnerablechamilo
  • cpe:2.3:a:chamilo:chamilo_lms:2.0.0:rc2:*:*:*:*:*:* Versions 2.0.0 rc2 Vulnerable ·chamilo

Remediation

  • Fix · CNA chamilo-lms (chamilo) Fixed in 2.0.0-RC.3

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-34161

References

Patch 2

Advisory 1

Other 1

  • TI-2025-32070 Chamilo: Evaluation of untrusted user input leads to Remote Code Execution CVSS 3.1CRITICAL 9.8
  • TI-2025-32081 Deserialization of untrusted data in chamilo-lms CVSS 4.0HIGH 8.8
  • TI-2024-32140 Chamilo: Post-Auth Remote Code Execution CVSS 4.0HIGH 8.7
  • TI-2023-03907 Chamilo LMS Unauthenticated Big Upload File Remote Code Execution CVSS 3.1HIGH 8.1
  • TI-2025-32595 Chamilo: Stored XSS Vulnerability via CSV User Import CVSS 3.1HIGH 8.8
  • TI-2024-20321 Chamilo LMS 1.11.26 is vulnerable to Incorrect Access Control via main/auth/profile. CVSS 3.1HIGH 8.8
See all 121 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences