{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "0"
                  },
                  {
                    "fixed": "1.45.2"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              },
              {
                "range": [
                  {
                    "fixed": "78123a2755c907c602e02352aebed4be86aa5350"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "range": [
                  {
                    "fixed": "faa72dae511ae64a7bf8ca63eff9ad4387d0b939"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "original_tag": "v1.45.2",
                "range": [
                  {
                    "fixed": "ad755945ad69008219e661c33ff1d72ff1bbcb51"
                  }
                ],
                "source": "REFERENCES_TAG"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "ad755945ad69008219e661c33ff1d72ff1bbcb51"
            },
            {
              "fixed": "78123a2755c907c602e02352aebed4be86aa5350"
            },
            {
              "fixed": "faa72dae511ae64a7bf8ca63eff9ad4387d0b939"
            }
          ],
          "repo": "https://github.com/open-telemetry/opentelemetry-python",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-mf5v-w3w3-f6cg"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-1333"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126360.json"
  },
  "details": "OpenTelemetry Python provides the Python API and SDK for OpenTelemetry. Prior to 1.45.2, TraceContextTextMapPropagator.extract() in opentelemetry-api can perform quadratic-time regular-expression backtracking on a malformed traceparent value containing a trace-context prefix, a long whitespace sequence, and an embedded newline. Exploitation requires an attacker-controlled carrier that preserves embedded newlines and permits a sufficiently large value, because conforming HTTP header values cannot contain embedded newlines. JSON-based carriers, including applicable MCP request metadata integrations, can preserve the required newline depending on the SDK, instrumentation, and message-size limits. Parsing on an asynchronous server's event-loop thread can consume excessive CPU and delay unrelated requests, while the advisory does not establish disclosure, modification, or code execution. This issue is fixed in version 1.45.2.",
  "id": "CVE-2026-126360",
  "modified": "2026-11-14T02:30:24.659346765Z",
  "published": "2026-11-12T22:24:22.023Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.45.2"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/126xxx/CVE-2026-126360.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/open-telemetry/opentelemetry-python/security/advisories/GHSA-mf5v-w3w3-f6cg"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126360"
    },
    {
      "type": "FIX",
      "url": "https://github.com/open-telemetry/opentelemetry-python/commit/78123a2755c907c602e02352aebed4be86aa5350"
    },
    {
      "type": "FIX",
      "url": "https://github.com/open-telemetry/opentelemetry-python/commit/faa72dae511ae64a7bf8ca63eff9ad4387d0b939"
    },
    {
      "type": "FIX",
      "url": "https://github.com/open-telemetry/opentelemetry-python/pull/5818"
    },
    {
      "type": "FIX",
      "url": "https://github.com/open-telemetry/opentelemetry-python/pull/5856"
    }
  ],
  "schema_version": "1.9.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "OpenTelemetry Python: Denial of service through quadratic-time traceparent parsing in opentelemetry-api"
}