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Public proof of conceptFix available

CVE-2023-39533

A public proof of concept exists; no exploitation attested.

  • Published2023-08-08
  • Fixed in0.29.1 · 0.28.2 · 0.27.8
  • WeaknessCWE-770

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2023-08-0819:15CVE publishedNVD

Versions per branch

OSV · NVD
Libp2p go-libp2p
BranchAffectedFixed in
0.29≥ 0.29.0, < 0.29.10.29.1
0.28≥ 0.28.0, < 0.28.20.28.2
0.27< 0.27.80.27.8
0.29= 0.29.0no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • libp2p go-libp2p
    Affected
    • = < 0.27.8no fix stated
    • = >= 0.28.0, < 0.28.2no fix stated
    • = = 0.29.0no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-09-01

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • golangAzure Linux:3all versions · fixed in 1.19.12-1
  • golangAzure Linux:3all versions · no fixed version listed
  • golangAzure Linux:3from 1.27.0 · no fixed version listed
  • golangAzure Linux:2from 1.19.0 · fixed in 1.19.12-1
  • golangAzure Linux:2all versions · fixed in 1.21.6-1
  • golangAzure Linux:2from 1.18.0 · fixed in 1.21.6-1
  • msft-golangAzure Linux:2all versions · fixed in 1.19.12-1

Vendor advisories

  • CVE-2023-39533 Red Hat Product Security

    go-libp2p: libp2p nodes vulnerable to attack using large RSA keys

Full record on NVD

Fix

  1. Update Libp2p go-libp2p to 0.29.1 · 0.28.2 · 0.27.8

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2024-10-10
  • CNACVSS 3.17.5known since 2026-10-23
  • NVDCVSS 3.17.5read 2026-10-23
  • CNAweakness (CWE)CWE-770known since 2026-10-23
  • FIRST EPSSEPSS score1.5 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2023-08-09

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2023-08-08
Last Modified
2026-09-01
NVD status
Modified
GitHub Advisory
GHSA-876p-8259-xjgg

Frequently asked questions

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.

Is CVE-2023-39533 actively exploited?

A proof-of-concept exploit exists for CVE-2023-39533, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2023-39533?

CVE-2023-39533 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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