Vulnerability · Published Oct 5, 2026 · Assigned by redhat

CVE-2026-105302Keycloak-services: keycloak-services: user session note mapper exposes upstream idp access tokens

Medium 5.7

In plain English

A medium-severity information exposure in Red Hat Build of Keycloak from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities).

Severity (CVSS 3.1)5.7Medium

Exploit odds (30 days)0.2%top 89.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
Red Hat	Red Hat Build of Keycloak	see references
Red Hat	Red Hat Build of Keycloak	see references
Red Hat	Red Hat Single Sign-On 7	see references

Weakness: CWE-200 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N

References

https://access.redhat.com/security/cve/CVE-2026-105302 vdb-entry, x_refsource_REDHAT
RHBZ#2545800 issue-tracking, x_refsource_REDHAT