# 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.

- **Severity:** Medium 5.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N`)
- **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 available:** No
- **Published:** 5 Oct 2026
- **Updated:** 5 Oct 2026
- **Also known as:** GHSA-3xph-hcf4-hx94

## 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 (Exposure of Sensitive Information to an Unauthorized Actor)

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-105302 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-105302 in the wild and no public exploit code.

Affected product: Red Hat Build of Keycloak. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-105302/ (Markdown: https://insights.sbomify.com/CVE-2026-105302/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-105302
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-105302
- OSV: https://osv.dev/vulnerability/CVE-2026-105302

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-105302/
Summaries are generated and may contain mistakes; the official description above is the record.