OpenClaw: Gateway WebSocket Denial of Service via unbounded pre-auth upgrades

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-41399: 0.32% estimated exploitation activity in the next 30 days; percentile 24.80 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The gateway accepted unbounded concurrent unauthenticated WebSocket upgrades before allocating them to an authenticated session budget. Impact An unauthenticated network attacker could consume socket and worker capacity and disrupt WebSocket availability for legitimate clients. 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 2026.3.28 contains the fix. Fix Fixed by commit cb5f7e201f (gateway: cap concurrent pre-auth websocket upgrades). Discovered by：Topsec AlphaLab (wang dong)

Published by the source

31 Mar 2026, 23:54 UTC

Last modified by the source

5 May 2026, 16:11 UTC

Source last checked

26 Oct 2026, 12:51 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-f44p-c7w9-7xr7

2. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-f44p-c7w9-7xr7

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# Patch Next advisory brief: CVE-2026-41399

Advisory: OpenClaw: Gateway WebSocket Denial of Service via unbounded pre-auth upgrades
IDs: CVE-2026-41399, GHSA-f44p-c7w9-7xr7
Record: https://patchnext.com/advisories/cve-2026-41399 (revision 3, source checked 26 Oct 2026, 12:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: openclaw 2026.3.28. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm openclaw: affected <= 2026.3.24; fixed in 2026.3.28

## Suggested inspection (read-only)
- `npm ls openclaw --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on openclaw.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-f44p-c7w9-7xr7 (OSV record GHSA-f44p-c7w9-7xr7 lists affected ranges: npm openclaw >=0 <2026.3.28 (fixed))
- Verified: https://github.com/advisories/GHSA-f44p-c7w9-7xr7 (GitHub-reviewed advisory GHSA-f44p-c7w9-7xr7 lists affected ranges: npm openclaw >=0 <=2026.3.24)

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