CVE-2026-73568

HIGHCVSS 7.5/10EPSS 0.49%

Last modified

CVE-2026-73568 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.49% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
0.49%

41.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
libp2ppy-libp2p<= 0.7.0

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is 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.
How severe is CVE-2026-73568?
CVE-2026-73568 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.49% probability of exploitation in the next 30 days.
How do I fix CVE-2026-73568?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST