CVE-2026-1529 is a high-severity (CVSS 8.1) CWE-347 vulnerability in org.keycloak:keycloak-services. 2 public exploit references exist, so weaponization risk is real. A fix is available for org.keycloak:keycloak-services — see the affected versions and patch details below.
Keycloak affected by improper invitation token validation
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-1529.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-1529 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
org.keycloak:keycloak-services☕org.keycloak:keycloak-services☕org.keycloak:keycloak-servicesReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.keycloak:keycloak-services | ≥ 26.5.0&&< 26.5.3 | 26.5.3org.keycloak:keycloak-services:26.5.3 |
| ☕Maven | org.keycloak:keycloak-services | all versions | 26.2.13org.keycloak:keycloak-services:26.2.13 |
| ☕Maven | org.keycloak:keycloak-services | ≥ 26.3.0&&< 26.4.9 | 26.4.9org.keycloak:keycloak-services:26.4.9 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-services, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.keycloak:keycloak-services to 26.5.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-1529 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-1529 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-1529. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This IMPORTANT flaw in Keycloak allows an attacker to register into an unauthorized organization. The vulnerability arises from improper cryptographic signature verification of organization invitation tokens, enabling modification of the organization ID and target email within the JWT payload.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat build of Keycloak 26.2 | rhbk/keycloak-operator-bundle:26.2.13-1 | RHSA-2026:2364 |
| Red Hat build of Keycloak 26.2.13 | rhbk/keycloak-rhel9 | RHSA-2026:2363 |
| Red Hat build of Keycloak 26.4 | rhbk/keycloak-operator-bundle:26.4.9-1 | RHSA-2026:2366 |
| Red Hat build of Keycloak 26.4.9 | rhbk/keycloak-rhel9 | RHSA-2026:2365 |
Frequently Asked Questions
Is CVE-2026-1529 in your dependencies?
O3 Security finds CVE-2026-1529 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.