py-libp2p: yamux connection DoS via oversized data frame

{
  "id": "788cf62b18f2ea1fb5e6fea02d1b6b07b4fb302523871aaa02aa0a1114c99b93",
  "url": "https://osv.dev/vulnerability/CVE-2026-73568",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "py-libp2p: yamux connection DoS via oversized data frame",
    "summary": "py-libp2p is the Python implementation of the libp2p networking stack. In 0.7.0 and earlier, the yamux handle_incoming() method in libp2p/stream_muxer/yamux/yamux.py reads an attacker-controlled 32-bit DATA frame length with read_exactly() before validating it against MAX_WINDOW_SIZE or checking whether stream_id exists. A peer that completes the standard Noise handshake can send a 12-byte frame declaring a 0xFFFFFFFF body and then withhold the body, causing the sequential yamux read loop used by the default new_host() configuration to block and preventing every stream on that connection from making progress. No fixed version is available as of this review.",
    "evidence": "osv:CVE-2026-73568",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-73568",
      "aliases": [
        "CVE-2026-73568",
        "GHSA-hmj8-5xmh-5573",
        "PYSEC-2026-3681"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/libp2p/py-libp2p",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "146ea87d1a20cc7dacf684ecf7c204543be04b37"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "0.7.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "146ea87d1a20cc7dacf684ecf7c204543be04b37"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.6.0",
            "v0.5.0",
            "v0.4.0",
            "v0.3.0",
            "v0.2.10",
            "v0.2.9",
            "v0.2.8",
            "v0.2.7",
            "v0.2.6",
            "v0.2.5",
            "v0.2.4",
            "v0.2.3",
            "v0.2.2",
            "v0.2.1",
            "v0.2.0",
            "v0.1.5",
            "v0.1.4",
            "v0.1.3",
            "v0.1.2",
            "v0.1.1",
            "v0.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-73568.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:53.325139705Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73568.json",
        "https://github.com/libp2p/py-libp2p/security/advisories/GHSA-hmj8-5xmh-5573",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-73568",
        "https://github.com/libp2p/py-libp2p/commit/146ea87d1a20cc7dacf684ecf7c204543be04b37"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-400"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73568.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-73568",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 522328,
  "published_at": "2026-08-13T17:43:26.065+00:00"
}