High severity · published Apr 9, 2026
CVE-2026-35640
OpenClaw < 2026.3.25 - Denial of Service via Unauthenticated Webhook Request Parsing
7.5
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 38% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
OpenClaw · OpenClaw
before 2026.3.25 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-35640
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-35640
Patch
https://github.com/openclaw/openclaw/commit/5e8cb22176e9235e224be0bc530699261eb60e53
Vendor Advisory
https://github.com/openclaw/openclaw/security/advisories/GHSA-3h52-cx59-c456
Third Party Advisory
https://www.vulncheck.com/advisories/openclaw-denial-of-service-via-unauthenticated-webhook-request-parsing
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