Cyber Resilience

CVE-2026-35665

DoS in Openclaw ≤ 2026.3.24

Public PoCDoS
Published
10 April 2026
Modified
13 April 2026
Patch / advisory
View advisory
CVSS Score v4 6.9
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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 0.0033 25th percentile
Risk Priority 40 floored blend · peak EPSS

Summary

CVE-2026-35665 is a medium-severity Amplification (CWE-405) vulnerability in Openclaw Openclaw. Its CVSS base score is 6.9 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Network Denial of Service (T1498); ranked at the 25th 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 SC-5 (Denial-of-service Protection) and SC-6 (Resource Availability) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

OpenClaw before 2026.3.24 contains an incomplete fix for CVE-2026-32011 where the Feishu webhook handler accepts request bodies with permissive limits of 1MB and 30-second timeout before signature verification. An unauthenticated attacker can exhaust server connection resources by sending concurrent slow…

more

HTTP POST requests to the Feishu webhook endpoint, blocking legitimate webhook deliveries.

CWE(s)
CWE-405

Related Threats

MITRE ATT&CK Enterprise Techniques

T1498 Network Denial of Service Impact
Adversaries may perform Network Denial of Service (DoS) attacks to degrade or block the availability of targeted resources to users.
attack.mitre.org →
T1499.002 Service Exhaustion Flood Impact
Adversaries may target the different network services provided by systems to conduct a denial of service (DoS).
attack.mitre.org →
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
attack.mitre.org →
T1498.002 Reflection Amplification Impact
Adversaries may attempt to cause a denial of service (DoS) by reflecting a high-volume of network traffic to a target.
attack.mitre.org →
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.001 OS Exhaustion Flood Impact
Adversaries may launch a denial of service (DoS) attack targeting an endpoint's operating system (OS).
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-35626Same product: Openclaw Openclaw
CVE-2026-28452Same product: Openclaw Openclaw
CVE-2026-32980Same product: Openclaw Openclaw
CVE-2026-28478Same product: Openclaw Openclaw
CVE-2026-41408Same product: Openclaw Openclaw
CVE-2026-32049Same product: Openclaw Openclaw
CVE-2026-41399Same product: Openclaw Openclaw
CVE-2026-42420Same product: Openclaw Openclaw
CVE-2026-41400Same product: Openclaw Openclaw
CVE-2026-29609Same product: Openclaw Openclaw

Affected Assets

openclaw
openclaw
≤ 2026.3.24

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

SC-5 Denial-of-service Protection good match

SC-5 directly requires mechanisms to limit the effects of asymmetric resource exhaustion attacks such as amplification DoS.

SC-6 Resource Availability good match

SC-6 enforces resource quotas and priority allocation that reduce the impact of unauthenticated or low-effort resource requests.

CM-7 Least Functionality partial match

Least-functionality disables unnecessary services or features that could be leveraged for amplification.

SC-7 Boundary Protection partial match

SC-7 boundary controls can filter or rate-limit traffic patterns that enable amplification without equivalent client work.

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.IR-03 mostly match
prevents

Resilience mechanisms such as rate limiting and load balancing directly constrain asymmetric resource use.

PR.IR-04 mostly match
prevents

Capacity planning and monitoring maintain availability headroom against amplification attacks.

DE.CM-01 partial match
prevents

Network monitoring detects amplification traffic patterns but does not itself limit asymmetric consumption.

DE.CM-09 partial match
prevents

Runtime resource monitoring can surface excessive consumption yet does not enforce authorization or work proofs.

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.8.6 Capacity management none match
mitigates

Stress-testing and demand-reduction tactics (e.g., bandwidth throttling) blunt amplification vectors that would otherwise let an attacker multiply resource consumption through a single request.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248553 OL 8 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-405
  • V-248552 OL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-405
Oracle Linux 9 (2 rules)
  • V-271709 OL 9 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-405
  • V-271710 OL 9 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-405
RHEL 8 (2 rules)
  • V-230244 RHEL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-405
  • V-244525 RHEL 8 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-405

References