CVE-2026-33580Network attack vector

Webhook event forgery via unthrottled signature failures

Published Mar 31, 2026 · Updated Mar 31, 2026

Missing rate limiting in OpenClaw before 2026.3.28 allows remote attackers to brute-force weak Nextcloud Talk webhook secrets. The webhook server's verifyWebhookSignature path returned 401 for every invalid signature without recording failures or limiting repeated requests. Reachability of the configured endpoint and a weak operator-configured secret are required; a recovered secret permits forged inbound webhook events.

CVSS severity6.3
Medium
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing rate limiting in OpenClaw before 2026.3.28 allows remote attackers to brute-force weak Nextcloud Talk webhook secrets. The webhook server's verifyWebhookSignature path returned 401 for every invalid signature without recording failures or limiting repeated requests. Reachability of the configured endpoint and a weak operator-configured secret are required; a recovered secret permits forged inbound webhook events.

The record

CVE
CVE-2026-33580
Published
Mar 31, 2026
Updated
Mar 31, 2026
Vendor
OpenClaw Foundation
Product
OpenClaw
Classifications
CWE-307, T1110
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=0 <2026.3.28

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenClaw Foundation · OpenClawversion=0 <2026.3.28

Published CVSS scores

6.5VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
6.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A: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.

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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-307Improper Restriction of Excessive Authentication Attempts
T1110Brute Force

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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