Vulnerability · Published Apr 9, 2026 · Assigned by VulnCheck

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

Medium 5.3

In plain English

A medium-severity security flaw in OpenClaw from OpenClaw. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.5%top 60.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	openclaw	2026.3.28	GHSA-3h52-cx59-c456

Affected products (as reported)

Vendor	Product	Versions
OpenClaw	OpenClaw	0 – before 2026.3.25

Weakness: CWE-696 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

GitHub Security Advisory (GHSA-3h52-cx59-c456) vendor-advisory
Patch Commit patch
VulnCheck Advisory: OpenClaw < 2026.3.25 - Denial of Service via Unauthenticated Webhook Request Parsing third-party-advisory