# CVE-2023-6787: Keycloak: session hijacking via re-authentication

> Attackers can hijack active Keycloak sessions and take over accounts by exploiting a flaw in the re-authentication mechanism when users cancel login prompts.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 25 Apr 2024
- **Updated:** 11 Nov 2025
- **Also known as:** GHSA-c9h6-v78w-52wj

## What is CVE-2023-6787?

CVE-2023-6787 is a medium-severity authentication bypass vulnerability in Redhat Build of Keycloak, published on 25 Apr 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A flaw was found in Keycloak that occurs from an error in the re-authentication mechanism within org.keycloak.authentication. This flaw allows hijacking an active Keycloak session by triggering a new authentication process with the query parameter "prompt=login," prompting the user to re-enter their credentials. If the user cancels this re-authentication by selecting "Restart login," an account takeover may occur, as the new session, with a different SUB, will possess the same SID as the previous session.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2023-6787?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.keycloak:keycloak-services` | Maven | All versions | 22.0.10 |
| `org.keycloak:keycloak-services` | Maven | All versions | 22.0.10 |
| `org.keycloak:keycloak-services` | Maven | From 23.0.0 | 24.0.3 |
| `org.keycloak:keycloak-services` | Maven | From 23.0.0 | 24.0.3 |

Products: Redhat Build of Keycloak, Redhat Keycloak.

## How do I fix CVE-2023-6787?

Upgrade org.keycloak:keycloak-services to a fixed version for your release line: 22.0.10 or 24.0.3.

## Is CVE-2023-6787 being exploited?

There is no known exploitation of CVE-2023-6787 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Build of Keycloak

- [CVE-2026-15572](https://insights.sbomify.com/CVE-2026-15572/): Keycloak-services: keycloak-services: dcr protocol mapper type-swap policy bypass allows privilege escalation (high 8.8)
- [CVE-2026-3047](https://insights.sbomify.com/CVE-2026-3047/): Keycloak SAML Broken has Authentication Bypass by Primary Weakness (high 8.8)
- [CVE-2026-15573](https://insights.sbomify.com/CVE-2026-15573/): Keycloak-services: keycloak-services: authorization bypass via unnormalized uri matching in pathmatcher (high 8.1)
- [CVE-2026-16102](https://insights.sbomify.com/CVE-2026-16102/): Keycloak-services: keycloak-services: default dcr policy allows role forgery via user property mappers (high 8.1)
- [CVE-2026-1609](https://insights.sbomify.com/CVE-2026-1609/): Org.keycloak/keycloak-quarkus-server: keycloak: unauthorized access via jwt authorization grant with disabled users (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-6787 and fix it if it is affected.

What it is: CVE-2023-6787 is a medium-severity authentication bypass vulnerability in Redhat Build of Keycloak, published on 25 Apr 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2023-6787 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.keycloak:keycloak-services (Maven): affected all versions; fixed in 22.0.10
- org.keycloak:keycloak-services (Maven): affected all versions; fixed in 22.0.10
- org.keycloak:keycloak-services (Maven): affected from 23.0.0; fixed in 24.0.3
- org.keycloak:keycloak-services (Maven): affected from 23.0.0; fixed in 24.0.3

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-2023-6787/ (Markdown: https://insights.sbomify.com/CVE-2023-6787/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-6787
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-6787
- OSV: https://osv.dev/vulnerability/CVE-2023-6787

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-6787/
Summaries are generated and may contain mistakes; the official description above is the record.