CVE-2026-41407Network attack vector

Secret-length disclosure via early comparison returns

Published Apr 28, 2026 · Updated Apr 28, 2026

Timing side channel in OpenClaw before 2026.4.2 allows remote attackers to infer shared-secret lengths through webhook requests. BlueBubbles, Feishu, Mattermost, Telegram, Twilio, Plivo, and Zalo handlers returned early or compared unequal-length buffers outside the shared safeEqualSecret helper. The leak requires repeated network measurements against a configured affected integration; it reveals length information but does not by itself bypass authentication.

CVSS severity6.3
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Timing side channel in OpenClaw before 2026.4.2 allows remote attackers to infer shared-secret lengths through webhook requests. BlueBubbles, Feishu, Mattermost, Telegram, Twilio, Plivo, and Zalo handlers returned early or compared unequal-length buffers outside the shared safeEqualSecret helper. The leak requires repeated network measurements against a configured affected integration; it reveals length information but does not by itself bypass authentication.

The record

CVE
CVE-2026-41407
Published
Apr 28, 2026
Updated
Apr 28, 2026
Vendor
OpenClaw Foundation
Product
OpenClaw
Classifications
CWE-208
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 28, 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 <2026.4.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenClaw Foundation · OpenClawversion=0 <2026.4.2

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
6.3VulnCheckCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
3.7VulnCheckCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/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.

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-208Observable Timing Discrepancy

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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