libp2p py-libp2p up to 0.7.0 yamux yamux.py handle_incoming infinite loop

Summaryinfo

A vulnerability categorized as problematic has been discovered in libp2p py-libp2p up to 0.7.0. The impacted element is the function handle_incoming of the file libp2p/stream_muxer/yamux/yamux.py of the component yamux. Such manipulation leads to infinite loop. This vulnerability is documented as CVE-2026-73568. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in libp2p py-libp2p up to 0.7.0. It has been rated as problematic. Affected by this issue is the function handle_incoming of the file libp2p/stream_muxer/yamux/yamux.py of the component yamux. The manipulation with an unknown input leads to a infinite loop vulnerability. Using CWE to declare the problem leads to CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. Impacted is availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-73568 since 08/12/2026. The exploitation is known to be easy. The attack may be launched remotely. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• libp2p

Name

• py-libp2p

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7.0

Website

• Product: https://github.com/libp2p/py-libp2p/

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