CVE-2026-35640
Received Received - Intake
Denial of Service via JSON Parsing in OpenClaw Webhooks

Publication date: 2026-04-09

Last updated on: 2026-04-15

Assigner: VulnCheck

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.
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Meta Information
Published
2026-04-09
Last Modified
2026-04-15
Generated
2026-06-16
AI Q&A
2026-04-10
EPSS Evaluated
2026-06-15
NVD
CVE-2026-35640
EUVD
EUVD-2026-21136
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
openclaw openclaw to 2026.3.25 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-696 The product performs multiple related behaviors, but the behaviors are performed in the wrong order in ways that may produce resultant weaknesses.
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Executive Summary

This vulnerability exists in OpenClaw versions before 2026.3.25. The software parses JSON request bodies before validating webhook signatures, which allows unauthenticated attackers to send malicious webhook requests. These requests force the server to perform resource-intensive JSON parsing operations before rejecting the request based on an invalid signature.

As a result, attackers can trigger a denial of service (DoS) by exhausting server resources through these forced parsing operations.

Impact Analysis

The primary impact of this vulnerability is a denial of service condition. Remote attackers can exploit it to exhaust server resources by sending malicious webhook requests that trigger expensive JSON parsing before signature validation.

This can lead to degraded performance or unavailability of the affected OpenClaw service, potentially disrupting normal operations.

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