What is CVE-2026-35665?

CVE-2026-35665 is a medium-severity vulnerability in Openclaw, classified under Asymmetric Resource Consumption (Amplification). CVSS score: 5.3/10. Published 2026-04-10.

How severe is CVE-2026-35665?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Openclaw

CVE-2026-35665

OpenClaw before 2026.3.24 contains an incomplete fix for CVE-2026-32011 where the Feishu webhook handler accepts request bodies with permissive limits of 1MB and 30-second timeout before signature verification. An unauthenticated attacker can exhaust server connection resources by sending concurrent slow HTTP POST requests to the Feishu webhook endpoint, blocking legitimate webhook deliveries.

EPSS: 0.003 (25.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Openclaw — versions 0, 2026.3.24

Weakness classification (CWE)

CWE-405 — Asymmetric Resource Consumption (Amplification)

References

disclosure@vulncheck.com (Exploit, vendor-advisory, Vendor Advisory, third-party-advisory)
disclosure@vulncheck.com (Third Party Advisory, third-party-advisory)

Frequently asked questions

What is CVE-2026-35665?: CVE-2026-35665 is a medium-severity vulnerability in Openclaw, classified under Asymmetric Resource Consumption (Amplification). CVSS score: 5.3/10. Published 2026-04-10.
How severe is CVE-2026-35665?: Medium severity. CVSS v3 base score is 5.3 out of 10.