# CVE-2023-6927: Keycloak: open redirect via "form_post.jwt" jarm response mode

> Attackers can steal authorization codes or tokens via an open redirect in the JARM response mode, potentially leading to account takeover.

- **Severity:** Medium 4.6 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/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:** Yes
- **Published:** 18 Dec 2023
- **Updated:** 22 Sep 2026
- **Also known as:** CVE-2023-6920, GHSA-9vm7-v8wj-3fqw

## What is CVE-2023-6927?

CVE-2023-6927 is a medium-severity vulnerability in Redhat Keycloak, published on 18 Dec 2023. 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 Keycloak. This issue may allow an attacker to steal authorization codes or tokens from clients using a wildcard in the JARM response mode "form_post.jwt" which could be used to bypass the security patch implemented to address CVE-2023-6134.

Weakness: CWE-601 (URL Redirection to Untrusted Site)

## Which versions are affected by CVE-2023-6927?

2 open source packages ship an affected version, including org.keycloak:keycloak-core. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.keycloak:keycloak-core` | Maven | All versions | 23.0.4 |
| `org.keycloak:keycloak-core` | Maven | All versions | 23.0.4 |

Products: Redhat Keycloak, Redhat Single Sign-On.

## How do I fix CVE-2023-6927?

Upgrade org.keycloak:keycloak-core to 23.0.4 or later.

## Is CVE-2023-6927 being exploited?

There is no known exploitation of CVE-2023-6927 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Keycloak

- [CVE-2022-4361](https://insights.sbomify.com/CVE-2022-4361/): Keycloak vulnerable to cross-site scripting when validating URI-schemes on SAML and OIDC (critical 10.0)
- [CVE-2022-1245](https://insights.sbomify.com/CVE-2022-1245/): Keycloak vulnerable to privilege escalation on Token Exchange feature (critical 9.8)
- [CVE-2021-20195](https://insights.sbomify.com/CVE-2021-20195/): keycloak Self Stored Cross-site Scripting vulnerability (critical 9.6)
- [CVE-2019-14910](https://insights.sbomify.com/CVE-2019-14910/): Keycloak Authentication Error (critical 9.3)
- [CVE-2019-14909](https://insights.sbomify.com/CVE-2019-14909/): Keycloak Authentication Error (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-6927 and fix it if it is affected.

What it is: CVE-2023-6927 is a medium-severity vulnerability in Redhat Keycloak, published on 18 Dec 2023. 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-2023-6927 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.keycloak:keycloak-core (Maven): affected all versions; fixed in 23.0.4
- org.keycloak:keycloak-core (Maven): affected all versions; fixed in 23.0.4

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-2023-6927/ (Markdown: https://insights.sbomify.com/CVE-2023-6927/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-6927
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-6927
- OSV: https://osv.dev/vulnerability/CVE-2023-6927

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-6927/
Summaries are generated and may contain mistakes; the official description above is the record.