CVE-2026-73568

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 v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/libp2p/py-libp2p/commit/146ea87d1a20cc7dacf684ecf7c204543be04b37
https://github.com/libp2p/py-libp2p/security/advisories/GHSA-hmj8-5xmh-5573
https://github.com/libp2p/py-libp2p/security/advisories/GHSA-hmj8-5xmh-5573

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-13 18:18

Updated : 2026-08-13 19:17

NVD link : CVE-2026-73568

Mitre link : CVE-2026-73568

CVE.ORG link : CVE-2026-73568

JSON object : View

Products Affected

No product.

CWE

CWE-400

Uncontrolled Resource Consumption

{"id": "CVE-2026-73568", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-73568", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-13T18:06:28.668080Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "libp2p", "product": "py-libp2p", "versions": [{"status": "affected", "version": "<= 0.7.0"}]}]}], "published": "2026-08-13T18:18:19.547", "references": [{"url": "https://github.com/libp2p/py-libp2p/commit/146ea87d1a20cc7dacf684ecf7c204543be04b37", "source": "security-advisories@github.com"}, {"url": "https://github.com/libp2p/py-libp2p/security/advisories/GHSA-hmj8-5xmh-5573", "source": "security-advisories@github.com"}, {"url": "https://github.com/libp2p/py-libp2p/security/advisories/GHSA-hmj8-5xmh-5573", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Received", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-400"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-08-13T19:17:35.323", "sourceIdentifier": "security-advisories@github.com"}