CVE-2025-59531
📋 TL;DR
Argo CD versions 1.2.0 through 3.2.0-rc1 contain a vulnerability where unauthenticated API requests with malformed Bitbucket Server payloads can crash the API server, causing denial of service. This affects all Argo CD deployments with the /api/webhook endpoint exposed and without a configured webhook.bitbucketserver.secret. Attackers can trigger CrashLoopBackOff states and potentially cause complete API outages.
💻 Affected Systems
- Argo CD
📦 What is this software?
Argo Cd by Argoproj
Argo Cd by Argoproj
Argo Cd by Argoproj
Argo Cd by Argoproj
Argo Cd by Argoproj
⚠️ Risk & Real-World Impact
Worst Case
Complete API server outage across all replicas, rendering Argo CD unusable and disrupting Kubernetes deployment workflows.
Likely Case
Partial or complete API server crashes causing intermittent or sustained denial of service to legitimate users.
If Mitigated
No impact if webhook.bitbucketserver.secret is configured or if vulnerable versions are not exposed to untrusted networks.
🎯 Exploit Status
Single malformed HTTP request triggers the crash, making exploitation trivial for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.14.20, 3.2.0-rc2, 3.1.8, 3.0.19
Vendor Advisory: https://github.com/argoproj/argo-cd/security/advisories/GHSA-f9gq-prrc-hrhc
Restart Required: Yes
Instructions:
1. Identify current Argo CD version. 2. Upgrade to patched version using Helm, kubectl, or Argo CD's upgrade process. 3. Restart Argo CD components. 4. Verify version and functionality.
🔧 Temporary Workarounds
Configure Bitbucket Server Webhook Secret
allSet webhook.bitbucketserver.secret to prevent malformed payload processing
argocd-cm ConfigMap: add 'webhook.bitbucketserver.secret: your-secret-here'
Restrict Webhook Endpoint Access
allUse network policies or firewalls to limit access to /api/webhook endpoint
kubectl apply network policies to restrict ingress to Argo CD API
🧯 If You Can't Patch
- Configure webhook.bitbucketserver.secret immediately
- Implement strict network controls to limit access to Argo CD API endpoints
🔍 How to Verify
Check if Vulnerable:
Check Argo CD version and verify webhook.bitbucketserver.secret is not configured in argocd-cm ConfigMapCheck Version:
kubectl get deployment argocd-server -o jsonpath='{.spec.template.spec.containers[0].image}' | grep -o 'v[0-9.]*'Verify Fix Applied:
Confirm version is patched (2.14.20+, 3.2.0-rc2+, 3.1.8+, 3.0.19+) and test webhook endpoint with malformed payload📡 Detection & Monitoring
Log Indicators:
- API server crash logs
- panic: runtime error: index out of range
- CrashLoopBackOff events in pod status
Network Indicators:
- HTTP POST requests to /api/webhook with malformed JSON
- Unusual traffic patterns to webhook endpoint
SIEM Query:
source="argo-cd" AND ("panic" OR "crash" OR "index out of range")