CVE-2026-41399Network attack vector

Service interruption via unbounded pre-auth WebSocket upgrades

Published Apr 28, 2026 · Updated Apr 28, 2026

Denial of service in OpenClaw Gateway before 2026.3.28 allows remote attackers to interrupt WebSocket service via upgrade floods. The Gateway upgrade handler accepts unlimited concurrent unauthenticated upgrades before assigning connections to a pre-authentication budget. Network reachability to the Gateway is sufficient; socket and worker exhaustion denies WebSocket access to legitimate clients.

CVSS severity8.7
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in OpenClaw Gateway before 2026.3.28 allows remote attackers to interrupt WebSocket service via upgrade floods. The Gateway upgrade handler accepts unlimited concurrent unauthenticated upgrades before assigning connections to a pre-authentication budget. Network reachability to the Gateway is sufficient; socket and worker exhaustion denies WebSocket access to legitimate clients.

The record

CVE
CVE-2026-41399
Published
Apr 28, 2026
Updated
Apr 28, 2026
Vendor
OpenClaw Foundation
Product
OpenClaw
Classifications
CWE-770, CWE-400, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2026.3.28

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenClaw Foundation · OpenClawversion=0 <2026.3.28

Published CVSS scores

7.5VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
CWE-400Uncontrolled Resource Consumption
T1499.002Service Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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