GHSA-f4xh-w4cj-qxq8: LangSmith SDK TracingMiddleware Arbitrary Server-side File Read Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-f4xh-w4cj-qxq8",
  "modified" : "2026-06-19T22:10:34Z",
  "published" : "2026-06-19T22:10:34Z",
  "aliases" : [ ],
  "summary" : "LangSmith SDK TracingMiddleware: Arbitrary server-side file read",
  "details" : "# Summary\n\nAn attacker who can send an HTTP request to a server running the LangSmith SDK's `TracingMiddleware` can cause that server to read an arbitrary file from its local filesystem and upload the contents to LangSmith as a trace attachment. Depending on how the distributed trace system is deployed, triggering a read may not require authentication. Retrieving the contents requires read access to the LangSmith workspace the traces are sent to. The net effect is a trust-boundary crossing: a party with workspace trace-read access (for example a low-privilege workspace member, a contractor, or a compromised teammate account) gains the ability to read files from any server running `TracingMiddleware`, a capability outside that workspace's intended trust boundary.\n\n# Impact\n\nConfidentiality (High): arbitrary read of files accessible to the server process, exposed to anyone with workspace trace-read access.\n\n# Details\n\nTwo defects combine. A field supplied through a tracing-propagation header was merged into the run without validation, allowing injection of run attributes including attachments (CWE-346). A type check intended to gate filesystem access did not match the type of the decoded input, so the guard never engaged (CWE-843). As a result, an attacker-named file is opened by the server and uploaded as a trace attachment by the background tracing thread (CWE-22).\n\n## Who can exploit this\n\n- Anyone reachable by HTTP can trigger the file read. Depending on how the distributed trace system is deployed, triggering may not require authentication.\n- Retrieving the file contents requires read access to the destination LangSmith workspace. The upload uses the server's own configured API key and workspace, which the attacker cannot redirect, so a zero-access outsider cannot retrieve the result; a workspace member, or anyone who has compromised one, can.\n\n# Remediation\n\nUpgrade the Python SDK to `>= 0.8.18`.\n\n# Workarounds\n\nUntil upgrading, do not expose `TracingMiddleware` to untrusted HTTP traffic, and limit workspace trace-read access to trusted members.\n\n# Credits\n\nFirst reported by @Ryu7zz.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "langsmith"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.8.18"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-f4xh-w4cj-qxq8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/langchain-ai/langsmith-sdk"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-22", "CWE-346", "CWE-843" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-19T22:10:34Z",
    "nvd_published_at" : null
  }
}