GHSA-JCC8-G2Q4-9FXQ

Vulnerability from github – Published: 2026-05-04 20:11 – Updated: 2026-07-21 14:54
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
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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
Show details on source website
To clipboard 

{
  "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": "2026-07-21T14:54:13Z",
  "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": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-42294"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2468443"
    },
    {
      "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"
    },
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42294.json"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "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"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.