Microsoft APM: Symlinks under `.apm/prompts/` and `.apm/agents/` are dereferenced during `apm install`, copying host-local file contents into the project tree

{
  "id": "d41d9084a98b773b0c245f1235719ea3541e37aacf0edd0b60041919f502868f",
  "url": "https://osv.dev/vulnerability/CVE-2026-45539",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Microsoft APM: Symlinks under `.apm/prompts/` and `.apm/agents/` are dereferenced during `apm install`, copying host-local file contents into the project tree",
    "summary": "Microsoft APM is an open-source, community-driven dependency manager for AI agents. From 0.5.4 to 0.12.4, two primitive integrators in apm-cli enumerate package files with bare Path.glob() / Path.rglob() calls and read each match with Path.read_text(), transparently following symbolic links. A symlink committed inside a remote APM dependency under .apm/prompts/.prompt.md or .apm/agents/.agent.md is preserved verbatim into apm_modules/ on clone and then dereferenced during integration, with the resolved content written as a regular file into the project's deploy directories. The package content_hash, the pre-deploy SecurityGate scan, and apm audit do not flag this. The deploy roots are not added to the auto-generated .gitignore, so the resulting files are staged by git add by default. This vulnerability is fixed in 0.13.0.",
    "evidence": "osv:CVE-2026-45539",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-45539",
      "aliases": [
        "CVE-2026-45539",
        "GHSA-q5pp-gvjg-h7v4",
        "PYSEC-2026-2377"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/microsoft/apm",
              "type": "GIT",
              "events": [
                {
                  "introduced": "56f47dff3c6aab6c5aef59126e5eacf3ef61795d"
                },
                {
                  "fixed": "921651639e4bc8231190d816ad4982a163529951"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.5.4"
                      },
                      {
                        "fixed": "0.13.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.13.0"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45539.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:26.641481994Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45539.json",
        "https://github.com/microsoft/apm/security/advisories/GHSA-q5pp-gvjg-h7v4",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-45539"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-200",
          "CWE-59"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45539.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-45539",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493379,
  "published_at": "2026-05-15T16:02:37.591+00:00"
}