Vulnerability Description
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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/libp2p/py-libp2p/commit/146ea87d1a20cc7dacf684ecf7c204543be04
- https://github.com/libp2p/py-libp2p/security/advisories/GHSA-hmj8-5xmh-5573
- https://github.com/libp2p/py-libp2p/security/advisories/GHSA-hmj8-5xmh-5573
FAQ
What is CVE-2026-73568?
CVE-2026-73568 is a vulnerability with a CVSS score of 7.5 (HIGH). 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-bi...
How severe is CVE-2026-73568?
CVE-2026-73568 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-73568?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.