CVE-2026-42437
Published: 05 May 2026
Summary
CVE-2026-42437 is a high-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability. Its CVSS base score is 8.2 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 33.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SC-5 (Denial-of-service Protection) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2026-42437 is a denial-of-service vulnerability (CWE-770) in OpenClaw versions 2026.4.9 and earlier, prior to 2026.4.10. The flaw occurs in the voice-call realtime WebSocket path, which fails to properly validate oversized frames. This issue, published on 2026-05-05, carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H), highlighting its potential for high-impact availability disruption without requiring privileges or user interaction.
Remote, unauthenticated attackers can exploit the vulnerability by sending oversized WebSocket frames to the affected voice-call realtime WebSocket path. In deployments exposing this webhook path, such attacks cause service unavailability, effectively denying service to legitimate users.
Advisories recommend upgrading to OpenClaw version 2026.4.10 or later, which includes the fix via the commit at https://github.com/openclaw/openclaw/commit/afadb7dae6738819ad9c7d2597ace0516957d20e. Further details on the vulnerability and remediation are provided in the GitHub security advisory at https://github.com/openclaw/openclaw/security/advisories/GHSA-vw3h-q6xq-jjm5 and the VulnCheck advisory at https://www.vulncheck.com/advisories/openclaw-denial-of-service-via-oversized-websocket-frames-in-voice-call-realtime-path.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-27257
Vulnerability details
OpenClaw versions 2026.4.9 before 2026.4.10 contain a denial of service vulnerability in the voice-call realtime WebSocket path that accepts oversized frames without proper validation. Remote attackers can send oversized WebSocket frames to cause service unavailability for deployments exposing the voice-call…
more
realtime WebSocket path.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The CVE describes a remotely exploitable software flaw (oversized WebSocket frame validation failure) that directly causes application-level resource exhaustion and service denial, matching T1499.004 Application or System Exploitation.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation of all inputs (including WebSocket frame sizes) to reject malformed or oversized data before it can exhaust resources.
Mandates denial-of-service protection mechanisms that limit the impact of resource-exhaustion attacks such as oversized WebSocket frames on the voice-call path.
Boundary-protection rules can restrict or filter traffic to the exposed voice-call realtime WebSocket endpoint, reducing the attack surface for unauthenticated oversized-frame DoS.