CVE-2026-31946
OpenOLAT: Authentication bypass via forged JWT in OIDC implicit flow
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
9.8
OpenOLAT: Authentication bypass via forged JWT in OIDC implicit flow
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.
- Record
CVE-2026-31946- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-287, CWE-347
- Updated
- 2026-11-02
EUVDEUVD-2026-17207
9.8
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.
- Record
EUVD-2026-17207- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
NVD
9.8
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.
- Record
CVE-2026-31946- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-287, CWE-347
- Updated
- 2026-11-02
OSV
9.8
OpenOLAT: Authentication bypass via forged JWT in OIDC implicit flow
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.
- Record
CVE-2026-31946- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-287, CWE-347
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-31946 is a critical vulnerability (CVSS 9.8) in Frentix Openolat, published March 30, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.21%, the 11th percentile. No source names a fixed version.