CVE intelligence

CVE-2023-39533

Vulnerability intelligence

Published Aug 8, 2023Sources checked Oct 30, 2026

7.5HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2023-39533 and is rated High severity with a CVSS score of 7.5. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Oct 21, 2026

CBL-Mariner Releases

Vendor-listed releases

1.21.6-1
1.19.12-1

CISA KEVNot listedBased on the latest collected catalog

EPSS1.5%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2023-39533?

go-libp2p is the Go implementation of the libp2p Networking Stack. Prior to versions 0.27.8, 0.28.2, and 0.29.1 malicious peer can use large RSA keys to run a resource exhaustion attack & force a node to spend time doing signature verification of the large key.

This vulnerability is present in the core/crypto module of go-libp2p and can occur during the Noise handshake and the libp2p x509 extension verification step. To prevent this attack, go-libp2p versions 0.27.8, 0.28.2, and 0.29.1 restrict RSA keys to <= 8192 bits.

To protect one's application, it is necessary to update to these patch releases and to use the updated Go compiler in 1.20.7 or 1.19.12. There are no known workarounds for this issue.

Source: NVD