CVE-2026-35640 OpenClaw < 2026.3.25 - Denial of Service via Unauthenticated Webhook Request Parsing

What is CVE-2026-35640?

CVE-2026-35640 is a medium-severity denial of service vulnerability in Openclaw Openclaw, published on 9 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

OpenClaw before 2026.3.25 parses JSON request bodies before validating webhook signatures, allowing unauthenticated attackers to force resource-intensive parsing operations. Remote attackers can send malicious webhook requests to trigger denial of service by exhausting server resources through forced JSON parsing before signature rejection.

Weakness: CWE-696

Which versions are affected by CVE-2026-35640?

2 open source packages ship an affected version, including openclaw. It affects 1 product.

Products include Openclaw Openclaw.

How do I fix CVE-2026-35640?

Upgrade openclaw to 2026.3.28 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-35640 being exploited?

There is no known exploitation of CVE-2026-35640 in the wild and no public exploit code.

Other vulnerabilities in Openclaw Openclaw

• CVE-2026-28363 Security feature bypass in OpenClaw Critical 9.9
• CVE-2026-30741 Code injection in n/a Critical 9.8
• CVE-2026-33579 OpenClaw < 2026.3.28 - Privilege Escalation via Missing Caller Scope Validation in Device Pair Approval Critical 9.4
• CVE-2026-32922 OpenClaw < 2026.3.11 - Privilege Escalation via Unvalidated Scope in device.token.rotate Critical 9.4
• CVE-2026-32978 OpenClaw < 2026.3.11 - Approval Bypass via Unrecognized Script Runners Critical 9.4

All Openclaw Openclaw vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-3h52-cx59-c456, MINI-8hm8-xfcg-qxj6.