Executive brief
OpenClaw is an AI gateway platform that includes a web_fetch tool for retrieving content from URLs. An attacker can craft a malicious webpage with an extremely large response body or deeply nested HTML structure, and trick users or automated systems into fetching it. This causes the Gateway process to exhaust memory and crash, resulting in a denial of service that disrupts all OpenClaw operations.
Technical details
The vulnerability is an uncontrolled resource consumption issue (CWE-400) in the web_fetch tool's response parsing logic. The component fails to validate or cap response body size before attempting to parse HTML, allowing an attacker to send arbitrarily large responses or pathological HTML with extreme nesting depth. This triggers out-of-memory (OOM) conditions or resource exhaustion in the Gateway process. The attack requires social engineering to convince a user or automation to fetch a malicious URL, but requires no authentication. The fix, applied in version 2026.2.15, adds response body size limits before parsing and additional guards for pathological HTML structures.
Affected products
- OpenClaw OpenClaw <= 2026.2.14
Timeline
- 2026-02-19: disclosed
- 2026-02-15: patched: Fix commit 166cf6a3e04c7df42bea70a7ad5ce2b9df46d147
- 2026-02-16: other: Patch published in version 2026.2.15