Cyber Resilience

CVE-2026-35628

Openclaw ≤ 2026.3.25

Public PoC
Published
09 April 2026
Modified
15 April 2026
Patch / advisory
CVSS Score v4 6.3
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0029 21th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-35628 is a medium-severity Improper Restriction of Excessive Authentication Attempts (CWE-307) vulnerability in Openclaw Openclaw. Its CVSS base score is 6.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Brute Force (T1110); ranked at the 21th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-7 (Unsuccessful Logon Attempts) and AC-3 (Access Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

OpenClaw before 2026.3.25 contains a missing rate limiting vulnerability in Telegram webhook authentication that allows attackers to brute-force weak webhook secrets. The vulnerability enables repeated authentication guesses without throttling, permitting attackers to systematically guess webhook secrets through brute-force attacks.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1110 Brute Force Credential Access
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained.
T1110.001 Password Guessing Credential Access
Adversaries with no prior knowledge of legitimate credentials within the system or environment may guess passwords to attempt access to accounts.
Why these techniques?

Missing rate limiting directly enables brute-force guessing of webhook secrets via repeated authentication attempts.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-35623Same product: Openclaw Openclaw
CVE-2026-35646Same product: Openclaw Openclaw
CVE-2026-33580Same product: Openclaw Openclaw
CVE-2026-34505Same product: Openclaw Openclaw
CVE-2026-32025Same product: Openclaw Openclaw
CVE-2026-62220Same product: Openclaw Openclaw
CVE-2026-41913Same product: Openclaw Openclaw
CVE-2026-32029Same product: Openclaw Openclaw
CVE-2026-41333Same product: Openclaw Openclaw
CVE-2026-28395Same product: Openclaw Openclaw

Affected Assets

openclaw
openclaw
≤ 2026.3.25

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-7 Unsuccessful Logon Attempts
  • AC-3 Access Enforcement
Detect
Catch it (NIST detect / respond)
  • SI-4 System Monitoring
Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly enforces limits on consecutive unsuccessful authentication attempts, eliminating the missing rate-limiting condition that enables brute-force of webhook secrets.

prevent

Access enforcement mechanisms can implement the required throttling policy on Telegram webhook authentication endpoints.

detect

Continuous monitoring of authentication traffic can identify repeated failed guesses against webhook secrets before they succeed.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 mostly match
prevents

Authentication enforcement directly includes lockout, throttling, and MFA policies that prevent brute-force attempts.

DE.CM-03 partial match
prevents

Behavioral monitoring of authentication activity can detect excessive failed attempts after they occur.

PR.PS-04 partial match
prevents

Generating auth logs enables later detection or forensics but does not itself restrict attempts.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

CAPTCHA, account lock-out after repeated failures, and alerts on excessive attempts directly stop automated brute-force guessing of credentials.

References