---
title: "CVE-2026-86038: libp2p @libp2p/gossipsub - Authentication Bypass"
description: "libp2p @libp2p/gossipsub 15.0.0 to 16.0.5 contains an authentication bypass caused by improper signature verification binding in buildRawMessage.ts, letting unauthenticated attackers impersonate victim RSA peer IDs, exploit requires crafted message with attacker-controlled keys."
url: https://panop.io/threat-heartbeat/CVE-2026-86038/
---

# CVE-2026-86038 libp2p @libp2p/gossipsub - Authentication Bypass

libp2p @libp2p/gossipsub 15.0.0 to 16.0.5 contains an authentication bypass caused by improper signature verification binding in buildRawMessage.ts, letting unauthenticated attackers impersonate victim RSA peer IDs, exploit requires crafted message with attacker-controlled keys.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.19% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-86038)

## Details

Type

Authentication Bypass

Impact

Broken Authentication

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Published

17 September 2026

Updated

15 October 2026

Weakness

[CWE-345](https://cwe.mitre.org/data/definitions/345.html)

## Vendor fix

Update to version 16.0.5 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-86038](https://nvd.nist.gov/vuln/detail/CVE-2026-86038)
- [https://github.com/libp2p/js-libp2p/security/advisories/GHSA-c3gv-825q-fvmp](https://github.com/libp2p/js-libp2p/security/advisories/GHSA-c3gv-825q-fvmp)
- [https://github.com/libp2p/js-libp2p/commit/cec2b1f349d130065e561349a0336a239528267f](https://github.com/libp2p/js-libp2p/commit/cec2b1f349d130065e561349a0336a239528267f)
- [https://github.com/libp2p/js-libp2p/pull/3569](https://github.com/libp2p/js-libp2p/pull/3569)
- [https://github.com/libp2p/js-libp2p/releases/tag/gossipsub-v16.0.5](https://github.com/libp2p/js-libp2p/releases/tag/gossipsub-v16.0.5)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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