GHSA-9JG3-G3WH-W9PJ

Vulnerability from github – Published: 2026-08-28 17:20 – Updated: 2026-08-28 17:20
VLAI
Summary
Yamcs has Unauthenticated Directory Traversal
Details

Attack type:

Unauthenticated remote 

Impact:

Attackers can access any system files from the underlying host.

Affected components: HttpRequestHandler.java, StaticFileHandler.java

An Unauthenticated Directory Traversal vulnerability exists in Yamcs <=5.8.6, allowing anyone to access any file on the underlying operating system. This allows unauthenticated attackers to download sensitive files and data.

image

Steps to Reproduce:

  1. Start Yamcs and login as a user
  2. Paste the following URL in the browser and press enter:
http://localhost:8090//etc/passwd
  1. The /etc/passwd file will be downloaded.

Acknowledgements

This vulnerability was discovered by Abderrahim Dahmani while solving a STARPWN 2025 CTF challenge at DEFCON 33 offered by VisionSpace Technologies.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c 5.11.13"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.yamcs:yamcs-core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.12.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-55552"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-28T17:20:42Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Attack type:\u202f\nUnauthenticated remote\u202f \n\n### Impact: \nAttackers can access any system files from the underlying host.\n\n### Affected components: HttpRequestHandler.java, StaticFileHandler.java\n\nAn Unauthenticated Directory Traversal vulnerability exists in Yamcs \u003c=5.8.6, allowing anyone to access any file on the underlying operating system. This allows unauthenticated attackers to download sensitive files and data.\n\n\u003cimg width=\"2170\" height=\"1289\" alt=\"image\" src=\"https://github.com/user-attachments/assets/8d426da1-5351-4240-a290-8d858be61312\" /\u003e\n\n## Steps to Reproduce:\n1. Start Yamcs and login as a user\n2. Paste the following URL in the browser and press enter:\n\n```\nhttp://localhost:8090//etc/passwd\n```\n\n3. The `/etc/passwd` file will be downloaded.\n\n## Acknowledgements\nThis vulnerability was discovered by Abderrahim Dahmani while solving a STARPWN 2025 CTF challenge at DEFCON 33 offered by VisionSpace Technologies.",
  "id": "GHSA-9jg3-g3wh-w9pj",
  "modified": "2026-08-28T17:20:42Z",
  "published": "2026-08-28T17:20:42Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/yamcs/yamcs/security/advisories/GHSA-9jg3-g3wh-w9pj"
    },
    {
      "type": "WEB",
      "url": "https://github.com/yamcs/yamcs/commit/c7dfd24e469ae1086c23e0fe04401cb1ce4260d4"
    },
    {
      "type": "WEB",
      "url": "https://github.com/yamcs/yamcs/commit/f4bc588880c166849e983aa8f65b9c8107d06091"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/yamcs/yamcs"
    },
    {
      "type": "WEB",
      "url": "https://github.com/yamcs/yamcs/releases/tag/yamcs-5.11.13"
    },
    {
      "type": "WEB",
      "url": "https://github.com/yamcs/yamcs/releases/tag/yamcs-5.12.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Yamcs has Unauthenticated Directory Traversal"
}



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