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9.3
CVE-2026-80428: ILIAS allows unauthenticated user to execute code via logout
CVE-2026-80428 · published 8 days ago
Summary
The ILIAS learning platform’s logout URL can be called by anyone, even without logging in. When it runs, it automatically converts stored session information into live objects without validation, letting an attacker insert data that causes the system to write and run their own code on the server. Upgrade to the newest ILIAS release that removes this logout handling, or apply the vendor’s patch, and restrict access to the logout endpoint.
What to do
- Update ilias-elearning e.v. ilias to version 9.22 or later.
Affected software
| Vendor | Product | Affected versions |
|---|---|---|
| ilias-elearning e.v. | ilias | < 9.22 |
Original advisory text
ILIAS deserialises stored session data for an unauthenticated caller. The Shibboleth back-channel endpoint at components/ILIAS/AuthShibboleth/resources/shib_logout.php runs in a context that ilInit...
ILIAS deserialises stored session data for an unauthenticated caller. The Shibboleth back-channel endpoint at components/ILIAS/AuthShibboleth/resources/shib_logout.php runs in a context that ilInitialisation exempts from authentication, and its logout-notification handler locates the session to terminate by reading every live row of the session table and passing each row's stored data to a hand-written parser that calls unserialize without restricting which classes may be constructed. Any serialised object present in any session row is therefore instantiated on behalf of an anonymous request, and object destructors run when those objects are discarded. A serialised object can be placed into a session row without logging in, because the LTI authentication entry point stores request parameters into the session and is reachable on a path the same initialisation code exempts from authentication. A class bundled with the application writes a JSON-encoded structure to a file named by one of its own properties when it is destroyed, which places attacker-controlled content at an attacker-chosen path below the web root and results in code execution as the web server user. Versions 9.22, 10.10 and 11.3 remove the endpoint's logout-notification implementation.
References
- https://github.com/ILIAS-eLearning/ILIAS product
- https://github.com/ILIAS-eLearning/ILIAS/commit/f36934a6f937d0fe837ca6e642986458... patch
- https://www.vulncheck.com/advisories/ilias-before-9.22-10.10-and-11.3-unauthenti... third-party-advisory
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80428... Vendor Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2026-80428 Vendor Advisory
Severity
9.3
Critical
CVSS 3.1: 9.8 (MITRE)
CVSS 4.0: 9.9 (OSV)
Exploitation
EPSS <1%
Type
CWE-502Deserialization of Untrusted Data
Timeline
Published26 Aug 2026
Updated3 Sep 2026
First seen29 Aug 2026
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