CVE-2026-42294: Argo Workflows Webhook Interceptor Denial of Service Vulnerability
Summary
CVE-2026-42294: Argo Vulnerable to Unauthenticated Memory Exhaustion (DoS) in Webhook Interceptor. Affects github.com/argoproj/argo-workflows/v3 versions < 3.7.14. Fixed in 3.7.14. How to fix ↓
Also tracked for
- github.com/argoproj/argo-workflows · Go
- argo-workflows · Bitnami
The same CVE-2026-42294 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 Workflows is an open-source container-native workflow engine for Kubernetes. It enables users to define workflows using YAML and manage complex workflows in a Kubernetes environment. The Webhook Interceptor is a component that authenticates incoming webhook requests. However, it has a vulnerability that allows for unauthenticated memory exhaustion, which can lead to denial of service.
Vulnerability Detail
The vulnerability arises from the Webhook Interceptor's design, where it loads the entire request body into memory before performing any authentication or signature verification. This occurs on the publicly accessible /api/v1/events/ endpoint. An attacker can exploit this by sending a request with a very large body, potentially several gigabytes in size, causing the Argo Server to allocate excessive memory. This can lead to an Out-Of-Memory (OOM) crash, resulting in denial of service and disrupting workflow execution and API access for all users.
How To Fix
Latest published version: v3.7.18 as of 22 Oct 2026
go get github.com/argoproj/argo-workflows/v3@v3.7.18Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
3.7.14
This is the first release that contains the fix.
go get github.com/argoproj/argo-workflows/v3@v3.7.14Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, you can enforce a strict limit on the size of the webhook body by using http.MaxBytesReader in your server configuration. Here is an example code snippet:
http.HandleFunc("/api/v1/events/", func(w http.ResponseWriter, r *http.Request) {
r.Body = http.MaxBytesReader(w, r.Body, 10*1024*1024) // Limit to 10MB
// ... handle the request ...
})
Conclusion
In summary, CVE-2026-42294 is a significant vulnerability in the Argo Workflows Webhook Interceptor that can lead to denial of service through memory exhaustion. It is crucial to update to the patched versions or implement workarounds to mitigate the risk.
See every vulnerability recorded for github.com/argoproj/argo-workflows/v3 →
FAQ
CVE-2026-42294 is a vulnerability in the Argo Workflows Webhook Interceptor that allows for denial of service through unauthenticated memory exhaustion.
An attacker can exploit this vulnerability by sending a request with an extremely large body to the /api/v1/events/ endpoint, causing the server to allocate excessive memory.
The consequences include potential crashes of the Argo Server, leading to service unavailability and disruption of workflows for all users.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without requiring any signup.
The CVSS score of this vulnerability is 8.2, indicating a high severity level.
References
Related vulnerabilities
Recent vulnerabilities recorded for github.com/argoproj/argo-workflows/v3.
