GHSA-JCC8-G2Q4-9FXQ

Vulnerability from github – Published: 2026-05-04 20:11 – Updated: 2026-05-13 13:39
VLAI?
Summary
Argo Vulnerable to Unauthenticated Memory Exhaustion (DoS) in Webhook Interceptor
Details

Severity: Medium Component: Webhook Interceptor (server/auth/webhook) Vulnerability Type: Denial of Service (DoS)

Description

The Webhook Interceptor loads the entire request body into memory before authenticating the request or verifying its signature. This occurs on the /api/v1/events/ endpoint, which is publicly accessible (albeit intended for webhooks). An attacker can send a request with an extremely large body (e.g., multiple gigabytes), causing the Argo Server to allocate excessive memory, potentially leading to an Out-Of-Memory (OOM) crash and denial of service.

Vulnerable Code

In server/auth/webhook/interceptor.go:

func (i *WebhookInterceptor) addWebhookAuthorization(r *http.Request, kube kubernetes.Interface) error {
    // ... basic checks ...

    // Vulnerability: Reads entire body into memory unconditionally
    buf, _ := io.ReadAll(r.Body)
    defer func() { r.Body = io.NopCloser(bytes.NewBuffer(buf)) }()

    // ... subsequent logic finds correct service account and secret ...
    // ... verification happens later ...
}

The io.ReadAll call happens before the signature verification loop.

Impact

  • Service Availability: An attacker can crash the Argo Server, disrupting workflow execution and API access for all users.

PoC (Conceptual)

  1. Target the webhook endpoint: POST /api/v1/events/some-namespace
  2. Send a Content-Length: 1000000000 (1GB) header.
  3. Stream 1GB of random data.
  4. Monitor server memory usage. It will spike until 1GB is allocated or the process crashes.

Recommendation

  1. Limit Body Size: Enforce a strict limit on webhook body size (e.g., 10MB) using http.MaxBytesReader.
  2. Streaming Verification: If possible, verify the signature in a streaming fashion or use a temporary file for large payloads (though typically webhooks are small).
Severity ?
8.2 (High)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/argoproj/argo-workflows/v3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.7.14"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/argoproj/argo-workflows/v4"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "4.0.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-42294"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-04T20:11:01Z",
    "nvd_published_at": "2026-05-09T04:16:24Z",
    "severity": "HIGH"
  },
  "details": "**Severity:** Medium\n**Component:** Webhook Interceptor (`server/auth/webhook`)\n**Vulnerability Type:** Denial of Service (DoS)\n\n## Description\nThe Webhook Interceptor loads the entire request body into memory before authenticating the request or verifying its signature. This occurs on the `/api/v1/events/` endpoint, which is publicly accessible (albeit intended for webhooks). An attacker can send a request with an extremely large body (e.g., multiple gigabytes), causing the Argo Server to allocate excessive memory, potentially leading to an Out-Of-Memory (OOM) crash and denial of service.\n\n## Vulnerable Code\nIn `server/auth/webhook/interceptor.go`:\n```go\nfunc (i *WebhookInterceptor) addWebhookAuthorization(r *http.Request, kube kubernetes.Interface) error {\n    // ... basic checks ...\n    \n    // Vulnerability: Reads entire body into memory unconditionally\n    buf, _ := io.ReadAll(r.Body)\n    defer func() { r.Body = io.NopCloser(bytes.NewBuffer(buf)) }()\n    \n    // ... subsequent logic finds correct service account and secret ...\n    // ... verification happens later ...\n}\n```\nThe `io.ReadAll` call happens before the signature verification loop.\n\n## Impact\n- **Service Availability:** An attacker can crash the Argo Server, disrupting workflow execution and API access for all users.\n\n## PoC (Conceptual)\n1.  Target the webhook endpoint: `POST /api/v1/events/some-namespace`\n2.  Send a `Content-Length: 1000000000` (1GB) header.\n3.  Stream 1GB of random data.\n4.  Monitor server memory usage. It will spike until 1GB is allocated or the process crashes.\n\n## Recommendation\n1.  **Limit Body Size:** Enforce a strict limit on webhook body size (e.g., 10MB) using `http.MaxBytesReader`.\n2.  **Streaming Verification:** If possible, verify the signature in a streaming fashion or use a temporary file for large payloads (though typically webhooks are small).",
  "id": "GHSA-jcc8-g2q4-9fxq",
  "modified": "2026-05-13T13:39:16Z",
  "published": "2026-05-04T20:11:01Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/argoproj/argo-workflows/security/advisories/GHSA-jcc8-g2q4-9fxq"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42294"
    },
    {
      "type": "WEB",
      "url": "https://github.com/argoproj/argo-workflows/commit/7abb4de6c3599e2d5d960ba4d5de4cf1df109965"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/argoproj/argo-workflows"
    },
    {
      "type": "WEB",
      "url": "https://github.com/argoproj/argo-workflows/releases/tag/v3.7.14"
    },
    {
      "type": "WEB",
      "url": "https://github.com/argoproj/argo-workflows/releases/tag/v4.0.5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Argo Vulnerable to Unauthenticated Memory Exhaustion (DoS) in Webhook Interceptor"
}


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