Cyber Resilience

CVE-2026-42421

Openclaw ≤ 2026.4.8

Public PoC
Published
28 April 2026
Modified
30 April 2026
Patch / advisory
View advisory
CVSS Score v4 2.3
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:L/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 0.0019 9th percentile
Risk Priority 15 floored blend · peak EPSS

Summary

CVE-2026-42421 is a low-severity Insufficient Session Expiration (CWE-613) vulnerability in Openclaw Openclaw. Its CVSS base score is 2.3 (Low).

Operationally, exploitation aligns with the MITRE ATT&CK technique External Remote Services (T1133); ranked at the 9th 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-12 (Session Termination) and AC-3 (Access Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

OpenClaw before 2026.4.8 contains a session management vulnerability where existing WebSocket sessions survive shared gateway token rotation. Attackers can maintain unauthorized access to WebSocket connections after token rotation by exploiting the failure to disconnect existing shared-token sessions.

CWE(s)
CWE-613

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1133 External Remote Services Persistence
Adversaries may leverage external-facing remote services to initially access and/or persist within a network.
attack.mitre.org →
Why these techniques?

Session expiration flaw enables persistent unauthorized access to WebSocket remote service after token rotation.

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

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CVE-2026-32001Same product: Openclaw Openclaw
CVE-2026-28463Same product: Openclaw Openclaw
CVE-2026-41408Same product: Openclaw Openclaw

Affected Assets

openclaw
openclaw
≤ 2026.4.8

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-12 Session Termination
  • AC-3 Access Enforcement
  • SC-23 Session Authenticity
Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

AC-12 Session Termination good match
prevent

Directly requires termination of sessions (including WebSocket) upon token rotation or other invalidation events, eliminating the exact persistence flaw.

AC-3 Access Enforcement good match
prevent

Enforces that only currently valid tokens grant access, so rotated shared-gateway tokens immediately revoke prior WebSocket sessions.

SC-23 Session Authenticity partial match
prevent

Protects session authenticity by binding sessions to current credentials, preventing continued use of stale shared tokens after rotation.

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-01 mostly match
prevents

Credential lifecycle management directly includes enforcing session expiration to prevent reuse.

PR.AA-05 mostly match
prevents

Authorization policy enforcement and review covers terminating stale sessions to limit access scope.

PR.AA-03 partial match
prevents

Authentication mechanisms can incorporate session timeout checks but do not inherently address expiration policy.

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.

A.8.5 Secure authentication none match
none

Automatic termination of inactive sessions and limits on connection duration shrink the window during which a hijacked or unattended authenticated session can be exploited.

References