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CVE-2026-49866— libp2p: CPU DoS via oversized IHAVE and IWANT control message arrays

Quick assessment

Affected
libp2p js-libp2p
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

libp2p是libp2p组织开源的一个点对点网络协议栈。 libp2p 16.0.0之前版本存在资源管理错误漏洞，该漏洞源于@libp2p/gossipsub的defaultDecodeRpcLimits将maxIhaveMessageIDs和maxIwantMessageIDs设置为无限大，导致恶意构造的IHAVE和IWANT控制消息数组可同步迭代每4MB帧约180,000个消息ID，从而阻塞Node.js事件循环。

CVSS 7.5 · High EPSS 0.63% · P47

Affected Version Matrix 1

VendorProduct Version RangeStatus
libp2p js-libp2p < 16.0.0 affected
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I. Basic Information for CVE-2026-49866

Vulnerability Information
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Vulnerability Title
libp2p: CPU DoS via oversized IHAVE and IWANT control message arrays
Source: CVE Program / CVE List V5
Vulnerability Description
libp2p is a JavaScript Implementation of libp2p networking stack. Prior to 16.0.0, @libp2p/gossipsub defaultDecodeRpcLimits set maxIhaveMessageIDs and maxIwantMessageIDs to Infinity, allowing oversized IHAVE and IWANT control message arrays in message/decodeRpc.ts and gossipsub.ts to synchronously iterate roughly 180,000 message IDs per 4 MB frame and block the Node.js event loop. This issue is fixed in version 16.0.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
不加限制或调节的资源分配
Source: CVE Program / CVE List V5
Vulnerability Title
libp2p 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
libp2p是libp2p组织开源的一个点对点网络协议栈。 libp2p 16.0.0之前版本存在资源管理错误漏洞，该漏洞源于@libp2p/gossipsub的defaultDecodeRpcLimits将maxIhaveMessageIDs和maxIwantMessageIDs设置为无限大，导致恶意构造的IHAVE和IWANT控制消息数组可同步迭代每4MB帧约180,000个消息ID，从而阻塞Node.js事件循环。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
libp2p js-libp2p < 16.0.0 -

II. Public POCs for CVE-2026-49866

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 7312 chars
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III. Intelligence Information for CVE-2026-49866

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Patches & Fixes for CVE-2026-49866 (2)

Vendor Advisories for CVE-2026-49866 (1)

Other References for CVE-2026-49866 (1)

IV. Related Vulnerabilities

Same product: js-libp2p
Same vendor: libp2p
Same weakness: CWE-770

V. Comments for CVE-2026-49866

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