CVE-2026-34161: chamilo-lms · Cross-site Scripting
Affects chamilo-lmsSource CVE Database V5
Not known to be exploited · CVSS 5.1 Medium : upgrade to 2.0.0-RC.3 when convenient.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 12% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 2.0.0-RC.3
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 14 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade chamilo-lms to 2.0.0-RC.3.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| chamilochamilo-lms | Affected
| Fixed in
|
GitHubchamilo/chamilo-lmspkg:github/chamilo/chamilo-lmsOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in chamilo-lms version 2.0.0-RC.3. Users and administrators should upgrade to this version or later to remediate the vulnerability. Since no official vendor advisory or patch link is provided, verify the upgrade availability and instructions from the official chamilo project resources. Until upgraded, restrict authenticated user permissions to limit exposure and avoid accessing untrusted uploaded attachments.
Description
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.
References
- github.com/chamilo/chamilo-lms/security/advisories/GHSA-273p-jw9w-3g22 (opens in a new tab)
- github.com/chamilo/chamilo-lms/commit/7c4965e48769d1d06413836429e386816a465c7f (opens in a new tab)
- github.com/chamilo/chamilo-lms/commit/da671d66a146887be3a16eabc5dcf0a92c55f7da (opens in a new tab)
- github.com/chamilo/chamilo-lms/releases/tag/v2.0.0-RC.3 (opens in a new tab)