CVE-2026-39878 Chamilo stored XSS via user registration leads to admin account takeover
Unauthenticated attackers can inject scripts via registration to hijack admin sessions in Chamilo LMS, requiring an upgrade to secure the platform.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-39878?
CVE-2026-39878 is a critical cross-site scripting vulnerability in chamilo-lms, published on 20 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Chamilo LMS versions 1.11.38 and earlier contain a stored cross-site scripting vulnerability in the user registration form that allows any unauthenticated attacker to execute arbitrary JavaScript in an administrator's browser session, leading to full platform admin account takeover. This has been patched in 1.11.40.
Weakness: CWE-79
Which versions are affected by CVE-2026-39878?
How do I fix CVE-2026-39878?
No fix has been published for CVE-2026-39878 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-39878 being exploited?
There is no known exploitation of CVE-2026-39878 in the wild and no public exploit code.
Sources
Also known as GHSA-gcjp-f7jm-rrrg.