CVE-2026-35626Network attack vector

Unauthenticated resource exhaustion via pre-auth body buffering

Published Apr 9, 2026 · Updated Apr 9, 2026

Resource exhaustion in OpenClaw before 2026.3.22 allows remote attackers to interrupt its voice-call webhook service with crafted requests. VoiceCallWebhookServer reads attacker-controlled bodies into memory before checking required provider signature headers, using a 1 MB limit and 30-second timeout without a pre-authentication per-IP concurrency cap. The voice-call extension must expose its webhook endpoint; unauthenticated callers can consume bounded resources per request and amplify consumption through concurrent requests.

CVSS severity6.9
Medium
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Resource exhaustion in OpenClaw before 2026.3.22 allows remote attackers to interrupt its voice-call webhook service with crafted requests. VoiceCallWebhookServer reads attacker-controlled bodies into memory before checking required provider signature headers, using a 1 MB limit and 30-second timeout without a pre-authentication per-IP concurrency cap. The voice-call extension must expose its webhook endpoint; unauthenticated callers can consume bounded resources per request and amplify consumption through concurrent requests.

The record

CVE
CVE-2026-35626
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
OpenClaw Foundation
Product
OpenClaw
Classifications
CWE-405, CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2026.3.22

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenClaw Foundation · OpenClawversion=0 <2026.3.22

Published CVSS scores

5.3VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
6.9VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-405Asymmetric Resource Consumption (Amplification)
CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo