CVE-2026-35640
Openclaw ≤ 2026.3.25
Raw vector
CVSS: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:XSummary
CVE-2026-35640 is a medium-severity Incorrect Behavior Order (CWE-696) vulnerability in Openclaw Openclaw. Its CVSS base score is 6.9 (Medium).
Operationally, ranked at the 36th 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 SA-11 (Developer Testing and Evaluation) and RA-5 (Vulnerability Monitoring and Scanning) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-35640 is a denial-of-service vulnerability in OpenClaw versions prior to 2026.3.25. The issue stems from the software parsing JSON request bodies in webhook endpoints before validating signatures, which allows attackers to force resource-intensive parsing operations even on invalid requests. This flaw is classified under CWE-696 (Incorrect Behavior Order: Authorization) and carries a CVSS v3.1 base score of 5.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L), indicating medium severity primarily due to low-impact availability disruption.
Unauthenticated remote attackers can exploit this vulnerability by sending specially crafted malicious webhook requests containing large or complex JSON payloads. Since signature validation occurs after parsing, the server exhausts CPU and memory resources processing these payloads, leading to denial of service through resource exhaustion. No privileges, user interaction, or special access are required, making it accessible to any network adversary targeting exposed OpenClaw webhook endpoints.
Mitigation is addressed in the official GitHub security advisory (GHSA-3h52-cx59-c456) and a corresponding patch commit (5e8cb22176e9235e224be0bc530699261eb60e53), which reportedly reorder operations to validate signatures before JSON parsing. Security practitioners should update to OpenClaw 2026.3.25 or later, as detailed in the advisory and Vulncheck analysis, and review webhook configurations for exposure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-21136
Vulnerability Data
OpenClaw before 2026.3.25 parses JSON request bodies before validating webhook signatures, allowing unauthenticated attackers to force resource-intensive parsing operations. Remote attackers can send malicious webhook requests to trigger denial of service by exhausting server resources through forced JSON parsing before…
more
signature rejection.
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation at post-design stages can discover incorrect ordering of related behaviors before deployment.
Vulnerability scanning may surface order-related weaknesses after code is built but does not address their root cause.
Mandating a documented development process and standards enforces review of behavior ordering within the software lifecycle.
Security and privacy engineering principles applied during design and implementation directly require correct sequencing of operations to avoid introducing order-dependent flaws.
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.
Secure SDLC practices directly enforce correct sequencing of security-relevant operations during design and coding.
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.
Security testing can detect ordering flaws but does not prevent them during development.
Secure development life cycle mandates correct sequencing of security activities, directly preventing incorrect behavior order.
Secure system architecture and engineering principles require proper ordering of design and implementation steps.
Secure coding standards enforce correct execution order of security-critical operations.
Change management may catch order-related issues during reviews but does not address root cause.