Deserialization in Ilias-Elearning E.v. Ilias

CVE-2026-80428

ILIAS before versions 9.22, 10.10, and 11.3 contains an unauthenticated PHP object injection vulnerability that allows unauthenticated attackers to execute arbitrary code by injecting serialized objects through the LTI authentication endpoint and triggering deserialization via the Shibboleth back-channel logout endpoint. Attackers can write arbitrary serialized objects into session storage, then exploit an available POP gadget through the logout endpoint's unrestricted deserialization to write attacker-controlled PHP content to a web-accessible path and achieve remote code execution as the web server user.

Vulnerability class: Insecure Deserialization

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.047 (91.5th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 92nd percentile — 91.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-80428: rose from 0.007 to 0.047.

EPSS over last 30 days · oldest: 0.007 · newest: 0.047 · change: +0.039

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-80428?
CVE-2026-80428 is a critical-severity vulnerability in Ilias-Elearning E.v. Ilias, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-08-26.
How severe is CVE-2026-80428?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-80428 known to be exploited?
4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.