Which versions of OpenClaw are affected by CVE-2026-41399?

OpenClaw versions prior to 2026.3.28 contain a high-severity denial of service vulnerability that allows unauthenticated remote attackers to exhaust server resources through WebSocket connection…. A patch is available.

How to fix or mitigate CVE-2026-41399?

Within 24 hours: Inventory all OpenClaw deployments and confirm versions earlier than 2026.3.28; implement network-level rate-limiting on WebSocket upgrade requests. Within 7 days: Enable connection limits and resource throttling at the application or reverse proxy layer; establish monitoring for abnormal WebSocket connection patterns. Within 30 days: Upgrade to OpenClaw 2026.3.28 or later when available; validate patch deployment in non-production environments first.

OpenClaw CVE-2026-41399

Q: What is the CVSS score of CVE-2026-41399?

CVE-2026-41399 has a CVSS 4.0 base score of 8.7 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.1%.

EUVD-2026-26107 HIGH

Allocation of Resources Without Limits or Throttling (CWE-770)

2026-04-28 VulnCheck

Denial Of Service Openclaw

8.7

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

8.7 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Patch released

Apr 30, 2026 - 16:57 nvd

Patch available

Apr 28, 2026 - 21:31 EUVD

Re-analysis Queued

Apr 28, 2026 - 20:23 vuln.today

cvss_changed

Analysis Generated

Apr 28, 2026 - 20:05 vuln.today

CVSS changed

Apr 28, 2026 - 19:52 NVD

7.5 (HIGH) 8.7 (HIGH)

EUVD ID Assigned

Apr 28, 2026 - 19:30 euvd

EUVD-2026-26107

Analysis Generated

Apr 28, 2026 - 19:30 vuln.today

CVE Published

Apr 28, 2026 - 18:09 nvd

HIGH 8.7

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

3 npm packages depend on openclaw (3 direct, 0 indirect)

Ecosystem-wide dependent count for version 2026.3.28.

DescriptionCVE.org

OpenClaw before 2026.3.28 accepts unbounded concurrent unauthenticated WebSocket upgrades without pre-authentication budget allocation. Unauthenticated network attackers can exhaust socket and worker capacity to disrupt WebSocket availability for legitimate clients.

AnalysisAI

Denial of service in OpenClaw (pre-2026.3.28) allows remote unauthenticated attackers to exhaust server resources by flooding the application with concurrent WebSocket upgrade requests. The vulnerability stems from lack of rate-limiting and resource budgeting before authentication, enabling attackers to monopolize socket and worker thread capacity and block legitimate WebSocket clients. No active exploitation confirmed (not in CISA KEV), but the technical barrier is low given unauthenticated network access (CVSS:4.0 AV:N/AC:L/PR:N). VulnCheck reported this vulnerability with vendor advisory available on GitHub.

Technical ContextAI

This is a resource exhaustion vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) in OpenClaw's WebSocket handling subsystem. The affected product (cpe:2.3:a:openclaw:openclaw:*:*:*:*:*:*:*:*) fails to implement pre-authentication resource budgets or connection rate-limiting for WebSocket upgrade requests. WebSocket protocol (RFC 6455) begins with an HTTP Upgrade handshake - the vulnerable code allocates server-side socket descriptors and worker threads during this handshake phase without verifying caller identity or enforcing concurrency limits. An attacker can initiate thousands of upgrade handshakes simultaneously, consuming file descriptors (typically limited per process by ulimit) and thread pool resources, preventing the server from accepting new connections. This is distinct from application-layer DoS - the attack occurs at the protocol handshake layer before any authentication logic executes.

RemediationAI

Upgrade to OpenClaw version 2026.3.28 or later, which implements pre-authentication resource budgeting for WebSocket upgrade requests per the vendor advisory at https://github.com/openclaw/openclaw/security/advisories/GHSA-f44p-c7w9-7xr7. If immediate patching is not feasible, implement compensating controls at the network perimeter: deploy a reverse proxy (nginx, HAProxy, Cloudflare) with WebSocket connection rate-limiting rules (e.g., limit to 10 concurrent upgrade requests per source IP per minute) and total concurrent WebSocket connection caps. Trade-off: aggressive rate-limiting may block legitimate clients behind NAT/CGNAT sharing IP addresses - monitor false positive rates and adjust thresholds based on baseline traffic patterns. Additional mitigation: configure OS-level limits (ulimit -n) and application thread pool sizes as defense-in-depth, though this only delays exhaustion rather than preventing it. Block WebSocket upgrade paths entirely via firewall rules if WebSocket functionality is not required, but this breaks legitimate WebSocket-dependent features.