CVE-2026-31946

OpenOLAT: Authentication bypass via forged JWT in OIDC implicit flow

State: Published
Severity: 9.8 Critical
Published: Mar 30, 2026
Updated: Mar 31, 2026
Reserved: Mar 10, 2026

Description

OpenOlat is an open source web-based e-learning platform for teaching, learning, assessment and communication. From version 10.5.4 to before version 20.2.5, OpenOLAT's OpenID Connect implicit flow implementation does not verify JWT signatures. The JSONWebToken.parse() method silently discards the signature segment of the compact JWT (header.payload.signature), and the getAccessToken() methods in both OpenIdConnectApi and OpenIdConnectFullConfigurableApi only validate claim-level fields (issuer, audience, state, nonce) without any cryptographic signature verification against the Identity Provider's JWKS endpoint. This issue has been patched in version 20.2.5.

Scores

CVSS	Score	Vector	Source
3.1	9.8 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	GitHub_M

Weaknesses

CWE-287 Improper Authentication
CWE-347 Improper Verification of Cryptographic Signature

Affected Products

Product	Versions
OpenOLATOpenOLAT	>= 10.5.4, < 20.2.5Affected

References

https://github.com/OpenOLAT/OpenOLAT/security/advisories/GHSA-v8vp-x4q4-2vch

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