# CVE-2026-1529: Keycloak affected by improper invitation token validation

> Attackers can bypass invitation token signature checks to self-register into unauthorized organizations, gaining illicit access to protected resources.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Feb 2026
- **Updated:** 15 Jul 2026
- **Also known as:** ECHO-f035-45d7-d0f3, GHSA-hcvw-475w-8g7p, MINI-j66q-fw3q-j6pj, MINI-vpc7-5ghv-fvwx

## What is CVE-2026-1529?

CVE-2026-1529 is a high-severity authentication bypass vulnerability in Red Hat build of Keycloak 26.2, published on 9 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A flaw was found in Keycloak. An attacker can exploit this vulnerability by modifying the organization ID and target email within a legitimate invitation token's JSON Web Token (JWT) payload. This lack of cryptographic signature verification allows the attacker to successfully self-register into an unauthorized organization, leading to unauthorized access.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2026-1529?

6 open source packages ship an affected version, including org.keycloak:keycloak-services.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.keycloak:keycloak-services` | Maven | All versions | 26.2.13 |
| `org.keycloak:keycloak-services` | Maven | All versions | 26.2.13 |
| `org.keycloak:keycloak-services` | Maven | From 26.3.0 | 26.4.9 |
| `org.keycloak:keycloak-services` | Maven | From 26.3.0 | 26.4.9 |
| `org.keycloak:keycloak-services` | Maven | From 26.5.0 | 26.5.3 |
| `org.keycloak:keycloak-services` | Maven | From 26.5.0 | 26.5.3 |

## How do I fix CVE-2026-1529?

Upgrade org.keycloak:keycloak-services to a fixed version for your release line: 26.2.13, 26.4.9 or 26.5.3.

## Is CVE-2026-1529 being exploited?

There is no known exploitation of CVE-2026-1529 in the wild and no public exploit code.

Public exploit code:

- Keycloak: Unauthorized organization registration via improper invitation token validation (github_poc): https://github.com/0x240x23elu/CVE-2026-1529
- Keycloak: Unauthorized organization registration via improper invitation token validation (github_poc): https://github.com/0xlyvio/CVE-2026-1529-Keycloak-Exploit-Tool
- CVE-2026-1529 (PoC) is a critical vulnerability in Keycloak that allows unauthorized organization registration through improper invitation token validation. This exploit tool demonstrates the vulnerability by manipulating JWT tokens to register users in unauthorized organizations. (github_poc): https://github.com/ackemed/CVE-2026-1529-PoC-keycloak-unauthorized-registration-via-improper-invitation-token-validation

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-1529 and fix it if it is affected.

What it is: CVE-2026-1529 is a high-severity authentication bypass vulnerability in Red Hat build of Keycloak 26.2, published on 9 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-1529 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.keycloak:keycloak-services (Maven): affected all versions; fixed in 26.2.13
- org.keycloak:keycloak-services (Maven): affected all versions; fixed in 26.2.13
- org.keycloak:keycloak-services (Maven): affected from 26.3.0; fixed in 26.4.9
- org.keycloak:keycloak-services (Maven): affected from 26.3.0; fixed in 26.4.9
- org.keycloak:keycloak-services (Maven): affected from 26.5.0; fixed in 26.5.3
- org.keycloak:keycloak-services (Maven): affected from 26.5.0; fixed in 26.5.3

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-2026-1529/ (Markdown: https://insights.sbomify.com/CVE-2026-1529/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-1529
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-1529
- OSV: https://osv.dev/vulnerability/CVE-2026-1529

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-1529/
Summaries are generated and may contain mistakes; the official description above is the record.