# CVE-2026-42294: Argo Workflows denial of service in Webhook Interceptor

Source: https://junglewise.ai/threats/cve-2026-42294-argo-workflows-denial-of-service-in-webhook-interceptor  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-09. Updated: 2026-07-21  
License: CC BY 4.0 with a link back

CVE-2026-42294 · Severity: high · CVSS 7.5 · Published 2026-05-09

Argo Workflows is an open-source engine for orchestrating parallel jobs on Kubernetes. A vulnerability in its webhook processing component allows an unauthenticated attacker to crash the Argo Server by sending a specially crafted, large request. This results in a denial of service, preventing users from managing workflows or accessing the API.

Technologies: [Argo Project Argo Workflows](https://junglewise.ai/threats/technologies/workflows), [github.com/argoproj/argo-workflows (Go)](https://junglewise.ai/threats/technologies/github-com-argoproj-argo-workflows), [github.com/argoproj/argo-workflows/v2 (Go)](https://junglewise.ai/threats/technologies/github-com-argoproj-argo-workflows-v2), [github.com/argoproj/argo-workflows/v3 (Go)](https://junglewise.ai/threats/technologies/github-com-argoproj-argo-workflows-v3), [github.com/argoproj/argo-workflows/v4 (Go)](https://junglewise.ai/threats/technologies/github-com-argoproj-argo-workflows-v4). Vendors: [Argo Project](https://junglewise.ai/threats/vendors/argo-project), [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-42294 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42294 being exploited in the wild.

**How severe is CVE-2026-42294?** High severity, with a CVSS score of 7.5, published 9 May 2026.

**Which products and versions are affected?** Argo Project Argo Workflows < 3.7.14, >= 4.0.0, < 4.0.5, >= 4.0.0, < 4.0.5; github.com/argoproj/argo-workflows (Go) SEMVER:introduced=0; github.com/argoproj/argo-workflows/v2 (Go) SEMVER:introduced=0; github.com/argoproj/argo-workflows/v3 (Go) < 3.7.14, SEMVER:introduced=0,fixed=3.7.14; and 1 more.

**Is there a fix for CVE-2026-42294?** Yes. github.com/argoproj/argo-workflows/v3 (Go): upgrade to 3.7.14 or later; github.com/argoproj/argo-workflows/v4 (Go): upgrade to 4.0.5 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-42294 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-42294?** Check whether you run Argo Project Argo Workflows, github.com/argoproj/argo-workflows (Go), github.com/argoproj/argo-workflows/v2 (Go) or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/argoproj/argo-workflows/v3 (Go): upgrade to 3.7.14 or later

  ```sh
  go get github.com/argoproj/argo-workflows/v3@v3.7.14
  ```

- github.com/argoproj/argo-workflows/v4 (Go): upgrade to 4.0.5 or later

  ```sh
  go get github.com/argoproj/argo-workflows/v4@v4.0.5
  ```


## Technical details

The vulnerability is an 'Allocation of Resources Without Limits or Throttling' (CWE-770) within the Webhook Interceptor (`server/auth/webhook/interceptor.go`). The `addWebhookAuthorization` function uses `io.ReadAll` to load the entire HTTP request body into memory before performing authentication or signature verification. Because the `/api/v1/events/` endpoint is publicly accessible, a remote, unauthenticated attacker can send a multi-gigabyte payload, triggering an Out-Of-Memory (OOM) crash of the Argo Server. The issue is fixed in versions 3.7.14 and 4.0.5 by implementing request body size limits.

## Affected products

- argoproj argo-workflows/v3 < 3.7.14
- argoproj argo-workflows/v4 >= 4.0.0, < 4.0.5

## Identifiers

- CVE-2026-42294
- GHSA-jcc8-g2q4-9fxq
- GO-2026-5462

## Timeline

- 2026-04-23: disclosed: Initial disclosure to maintainers
- 2026-05-04: advisory: GitHub Advisory published
- 2026-05-09: advisory: NVD published CVE-2026-42294
- 2026-07-21: other: Advisory updated

## References

- [https://api.github.com/users/Rudra2018](https://api.github.com/users/Rudra2018)
- [https://github.com/Rudra2018](https://github.com/Rudra2018)
- [https://api.github.com/users/Rudra2018/gists%7B/gist_id%7D](https://api.github.com/users/Rudra2018/gists%7B/gist_id%7D)
- [https://api.github.com/users/Rudra2018/repos](https://api.github.com/users/Rudra2018/repos)
- [https://avatars.githubusercontent.com/u/36075950?v=4](https://avatars.githubusercontent.com/u/36075950?v=4)
- [https://api.github.com/users/Rudra2018/events%7B/privacy%7D](https://api.github.com/users/Rudra2018/events%7B/privacy%7D)

## Related threats

- [Argo Workflows authorization bypass in ListArchivedWorkflows](https://junglewise.ai/threats/cve-2026-93991-argo-workflows-versions-4-1-0-through-4-1-3-contain-an)
- [Argo Workflows privilege escalation via ArtifactGC PodSpecPatch](https://junglewise.ai/threats/cve-2026-54526-argo-workflows-privilege-escalation-via-artifactgc-podspecpatch)
- [Argo Workflows missing authorization in Sync ConfigMap Provider](https://junglewise.ai/threats/cve-2026-42297-argo-workflows-missing-authorization-in-sync-configmap-provider)
- [Argo Workflows authorization bypass in templateReferencing Strict mode](https://junglewise.ai/threats/cve-2026-42296-argo-workflows-authorization-bypass-in-templatereferencing-strict)
- [Argo Workflows plaintext credential leak in workflow logs](https://junglewise.ai/threats/cve-2026-42295-argo-workflows-plaintext-credential-leak-in-workflow-logs)