CVE-2025-59538: Argo CD Unauthenticated Remote DoS via Malformed Azure DevOps Webhook
Summary
CVE-2025-59538: Argo CD Unauthenticated Remote DoS via malformed Azure DevOps git.push webhook. Affects github.com/argoproj/argo-cd/v2 versions >= 2.9.0-rc1, < 2.14.20. Fixed in 2.14.20. How to fix ↓
Also tracked for
- github.com/argoproj/argo-cd · Go
- argo-cd · Bitnami
The same CVE-2025-59538 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
Argo CD is a declarative, GitOps continuous delivery tool for Kubernetes. It allows users to manage applications and their deployment states using Git repositories as the source of truth. Argo CD supports various webhook integrations, including Azure DevOps, to trigger application updates based on repository events. However, a vulnerability exists in the webhook handling logic that can lead to a denial of service (DoS) when specific malformed payloads are received.
Vulnerability Detail
The vulnerability arises from the lack of proper validation in the webhook handling code for Azure DevOps push events. When the webhook receives a payload with an empty 'refUpdates' array, it attempts to access the first element without checking the array's length. This results in an index-out-of-range panic, causing the entire argocd-server process to crash. An unauthenticated HTTP POST request with such a payload is sufficient to exploit this vulnerability, leading to a denial of service.
How To Fix
Latest published version: v2.14.21 as of 22 Oct 2026
go get github.com/argoproj/argo-cd/v2@v2.14.21Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
2.14.20
This is the first release that contains the fix.
go get github.com/argoproj/argo-cd/v2@v2.14.20Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If you are using Azure DevOps and need to handle webhook events, configure a webhook secret to ensure only trusted parties can invoke the webhook handler. If you do not use Azure DevOps, you can set the webhook secrets to long, random values to effectively disable webhook handling for Azure DevOps payloads. Here is an example of how to configure the secrets:
apiVersion: v1
kind: Secret
metadata:
name: argocd-secret
type: Opaque
data:
webhook.azuredevops.username: <your base64-encoded secret here>
webhook.azuredevops.password: <your base64-encoded secret here>
Conclusion
The CVE-2025-59538 vulnerability in Argo CD poses a significant risk of denial of service through unauthenticated webhook events. It is crucial to update to the latest patched versions or implement the recommended workarounds to mitigate the risk. Regular monitoring for vulnerabilities using tools like Vulert can help maintain the security of your applications.
See every vulnerability recorded for github.com/argoproj/argo-cd/v2 →
FAQ
CVE-2025-59538 is a vulnerability in Argo CD that allows unauthenticated remote denial of service via malformed Azure DevOps webhook payloads.
If exploited, this vulnerability can crash the argocd-server process, leading to downtime and disruption of application delivery.
Versions 2.9.0-rc1 to 2.14.19 and 3.1.0-rc1 to 3.1.7 are affected. Ensure to update to the patched versions.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in real-time. Visit Vulert Scanner to check if your application is affected without needing to sign up.
The CVSS score for this vulnerability is 7.5, indicating a high severity level.
References
Related vulnerabilities
Recent vulnerabilities recorded for github.com/argoproj/argo-cd/v2.
