ZITADEL: Unauthorized Token Privilege Escalation in OAuth2 Token ExchangeGHSA-vrh8-c9cm-wh8v
HIGHFix: zitadel/zitadel@e2886a6GHSA-vrh8-c9cm-wh8v is a high-severity (CVSS 8.1) CWE-862 vulnerability in github.com/zitadel/zitadel. A fix is available for github.com/zitadel/zitadel — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- 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 GHSA-vrh8-c9cm-wh8v.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
github.com/zitadel/zitadelReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A vulnerability in ZITADEL’s OAuth2 Token Exchange endpoint allows an authenticated user or client to exchange a low-privilege access token for a token with elevated permissions at a completely different application. This bypasses the intended authorization and separation policies configured within ZITADEL.
Impact
ZITADEL enables administrators to restrict token issuance based on client permissions, project roles, and specific scopes. Due to a missing verification step during the Token Exchange flow (urn:ietf:params:oauth:grant-type:token-exchange), ZITADEL fails to validate whether the incoming access token belongs to or is authorized for the client initiating the exchange. Additionally, ZITADEL does not enforce that the newly requested scopes must stay within the boundaries of the original token's scopes.
An attacker with valid access to a low-privilege application can exploit this behavior by sending a token exchange request to a highly-privileged target application. This allows them to obtain administrative project roles, access sensitive profile data, or gain unauthorized access to other applications across the system. If public clients (which do not require client secrets) are used, this risk increases significantly as it requires no client authentication.
Affected Versions
Systems running one of the following versions are affected:
- 4.x:
4.0.0through4.15.2(including RC versions) - 3.x:
3.0.0through3.4.12(including RC versions)
Patches
The vulnerability has been addressed in the latest releases. The patch resolves the issue by enforcing strict audience ownership verification and ensuring that requested scopes during a token exchange are restricted to a subset of the original token’s scopes.
Workarounds
The recommended solution is to upgrade to a patched version immediately. If an immediate upgrade is not possible, implement one of the following mitigations:
- Disable via Feature Flag: Ensure the Token Exchange feature flag is explicitly turned off in your instance settings or environment variables (
ZITADEL_DEFAULTINSTANCE_FEATURES_TOKENEXCHANGE=false). If the feature flag is disabled, the endpoint is unreachable and your system is not vulnerable. This is only possible in versions prior to v4.11.0, where the feature was not yet GA. - Remove the Grant Type: Ensure that the Token Exchange grant type is completely disabled or removed from all configured applications—especially high-privilege or public clients.
Questions
If you have any questions or comments about this advisory, please email us at [email protected].
Credits
Thanks to thesecguy45 and Shubham Raj / Causal Security for reporting this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/zitadel/zitadel | all versions | 4.15.3go get github.com/zitadel/zitadel@v4.15.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/zitadel/zitadel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/zitadel/zitadel to 4.15.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vrh8-c9cm-wh8v is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is GHSA-vrh8-c9cm-wh8v in your dependencies?
Find it across Go, including transitive dependencies.