CVE-2026-105302 Keycloak-services: keycloak-services: user session note mapper exposes upstream idp access tokens
A flaw in Keycloak's session note mapper allows client administrators to leak upstream identity provider access tokens, exposing user data on external platforms.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-105302?
CVE-2026-105302 is a medium-severity vulnerability in Red Hat Build of Keycloak, published on 5 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
A flaw was found in the User Session Note mapper of the Keycloak identity and access management solution. The issue occurs because the mapper does not validate whether a requested session note contains sensitive internal credentials, such as federated access tokens from external identity providers. This allows a delegated client administrator to leak a user's upstream bearer tokens into the tokens issued to their managed application, potentially leading to unauthorized access to the user's data on external platforms.
Weakness: CWE-200
Which versions are affected by CVE-2026-105302?
How do I fix CVE-2026-105302?
No fix has been published for CVE-2026-105302 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-105302 being exploited?
There is no known exploitation of CVE-2026-105302 in the wild and no public exploit code.
Sources
Also known as GHSA-3xph-hcf4-hx94.