{"id":"CVE-2026-73568","aliases":["GHSA-hmj8-5xmh-5573"],"url":"https://o3.security/vulnerability/CVE-2026-73568","summary":"py-libp2p: yamux connection DoS via oversized data frame","details":"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.","published":"2026-08-13T17:43:26.065Z","modified":"2026-08-14T04:03:59.862813037Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"PyPI","name":"libp2p","fixedVersion":null}],"fix":{"url":"https://github.com/libp2p/py-libp2p/commit/146ea87d1a20cc7dacf684ecf7c204543be04b37","label":"libp2p/py-libp2p@146ea87"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73568.json"},{"type":"FIX","url":"https://github.com/libp2p/py-libp2p/commit/146ea87d1a20cc7dacf684ecf7c204543be04b37"},{"type":"ADVISORY","url":"https://github.com/libp2p/py-libp2p/security/advisories/GHSA-hmj8-5xmh-5573"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-73568"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-14T04:03:59.862813037Z"}}