Summary
OpenClaw: Gateway WebSocket Denial of Service via unbounded pre-auth upgrades
The gateway accepted unbounded concurrent unauthenticated WebSocket upgrades before allocating them to an authenticated session budget.
Affected Component
src/gateway/server-http.ts, src/gateway/server/preauth-connection-budget.ts
Fixed Versions
- Affected:
<= 2026.3.24 - Patched:
>= 2026.3.28 - Latest stable
2026.3.28contains the fix.
Impact
An unauthenticated network attacker could consume socket and worker capacity and disrupt WebSocket availability for legitimate clients.
Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Fixed by commit cb5f7e201f (gateway: cap concurrent pre-auth websocket upgrades).
Discovered by：Topsec AlphaLab (wang dong)
Frequently Asked Questions
- What is CVE-2026-41399? CVE-2026-41399 is a medium-severity uncontrolled resource consumption vulnerability in openclaw (npm), affecting versions <= 2026.3.24. It is fixed in 2026.3.28. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
- Which versions of openclaw are affected by CVE-2026-41399? openclaw (npm) versions <= 2026.3.24 is affected.
- Is there a fix for CVE-2026-41399? Yes. CVE-2026-41399 is fixed in 2026.3.28. Upgrade to this version or later.
- Is CVE-2026-41399 exploitable, and should I be worried? Whether CVE-2026-41399 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-41399 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-41399? Upgrade
openclawto 2026.3.28 or later.