GHSA-29jh-8cfq-rr8x
GHSA-29jh-8cfq-rr8x is a security vulnerability in github.com/zitadel/zitadel. O3 Security confirms whether GHSA-29jh-8cfq-rr8x is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
ZITADEL: Server-Side Request Forgery (SSRF) and Denylist Bypass in Outgoing HTTP Components
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.
Blast Radius
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 Server-Side Request Forgery (SSRF) vulnerability was discovered in Zitadel affecting:
- HTTP Notification Channels: Used as an alternative to SMTP/Twilio configurations, sending payloads to user-defined URLs via HTTP POST webhooks.
- OIDC BackChannel Logout: Terminates sessions across different applications. When a session ends, the Zitadel server sends an HTTP POST request to configured endpoints.
- SAML Metadata URL Fetches: Fetches SAML metadata configurations from user-provided external URLs.
User-defined URLs in these components were not properly validated against an internal denylist, allowing potentially malicious URLs to bypass restrictions. Furthermore, the existing denylist mechanism previously introduced for Actions was found to be vulnerable to DNS rebinding, HTTP redirects, and protocol downgrades (HTTPS to HTTP), and it missed several common local network default entries.
Because an attacker can supply arbitrary URLs—including loopback addresses, internal IPs, or cloud link-local addresses—they could potentially gather internal network architecture details, scan internal ports, or interact with unauthorized internal services and infrastructure.
Impact
When a user-supplied URL points to a local host or internal IP address, an adversary can perform a Server-Side Request Forgery (SSRF) attack. This allows them to map internal network structures and exploit exposed internal services.
By leveraging DNS rebinding, an attacker could also bypass standard DNS-level checks, creating Time-of-Check to Time-of-Use (TOCTOU) gaps to access restricted internal endpoints. Additionally, vulnerabilities to HTTP redirects and protocol downgrades could allow attackers to manipulate the request flow or intercept sensitive communication.
Notably, if Zitadel is deployed within cloud environments (such as AWS, GCP, or Azure) that still permit legacy IMDSv1 or unauthenticated cloud metadata endpoints (169.254.169.254), an attacker could theoretically attempt to target these metadata services.
While Zitadel expects specific schemas or response formats for these features (which inherently limits data exfiltration capabilities and reduces the severe execution of the threat vector), users are strongly advised to patch immediately.
Affected Versions
Systems running one of the following versions are affected:
- 4.x:
4.0.0through4.15.1(including RC versions) - 3.x:
3.0.0through3.4.11(including RC versions)
Patches
The vulnerability has been addressed in the latest releases. The patch resolves the issue by securely validating target URLs against a hardened denylist. By default, localhost, loopback IPs, and standard internal network blocks are denied.
Note on Backports: This fix was only released on v4.x. While some of the affected components were generally available (GA), backporting the security fix to v3.x was not feasible due to the extensive code refactoring required to implement the unified network client securely. Please check the workarounds section if an upgrade to v4.x is not immediately possible.
Workarounds
The recommended solution is to update Zitadel to a patched version.
If an immediate upgrade is not possible, you can mitigate the risk by implementing strict network policies, egress firewalls, or reverse proxy rules within your infrastructure to block Zitadel from initiating outbound connections to your internal network, loopback interfaces, or cloud metadata endpoints. Note that managing these network controls is outside the scope of Zitadel's native configurations.
Questions
If you have any questions or comments about this advisory, please email us at [email protected]
Credits
Thanks to everyone who reported this or a part of the vulnerability:
- cwanglab
- wooseokdotkim
- ffulbtech
- 0xBassia
- 5ud0 from Tarmo Technologies
- alanturing881
- dungNHVhust and sondt99
- oduoke567
- DavidCarliez
- eddieran
- tikket1
- Wernerina
- morimori-dev
- vamsik2k5
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/zitadel/zitadel | all versions | 1.80.0-v2.20.0.20260615133614-8e82ec1cb9a2 |
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. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/zitadel/zitadel to 1.80.0-v2.20.0.20260615133614-8e82ec1cb9a2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-29jh-8cfq-rr8x 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 pinpoints whether GHSA-29jh-8cfq-rr8x is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-29jh-8cfq-rr8x. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-29jh-8cfq-rr8x in your dependencies?
O3 detects GHSA-29jh-8cfq-rr8x across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.