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OpenClaw has a Web Fetch DoS via unbounded response parsing

Moderate severity GitHub Reviewed Published Feb 18, 2026 in openclaw/openclaw • Updated Feb 19, 2026

Package

npm openclaw (npm)

Affected versions

< 2026.2.15

Patched versions

2026.2.15

Description

Summary

The web_fetch tool could be used to crash the OpenClaw Gateway process (OOM / resource exhaustion) by fetching and attempting to parse attacker-controlled web pages with oversized response bodies or pathological HTML nesting.

Affected Packages / Versions

  • Package: openclaw (npm)
  • Affected versions: <= 2026.2.14
  • Fixed versions: >= 2026.2.15

Impact

An attacker can social-engineer a user (or any automation that uses web_fetch) into fetching a malicious URL that returns extremely large or deeply nested HTML. The Gateway may exhaust memory or become unresponsive, causing a denial of service.

Fix

The Gateway now caps the downloaded response body size before any HTML parsing and adds additional guards to avoid running Readability/DOM parsing on pathological HTML.

Fix Commit(s)

  • 166cf6a3e04c7df42bea70a7ad5ce2b9df46d147

Release Process Note

This advisory is prepared for the next npm release. Once openclaw@2026.2.15 is published, publish this advisory without further edits.

Thanks @xuemian168 for reporting.

References

@steipete steipete published to openclaw/openclaw Feb 18, 2026
Published to the GitHub Advisory Database Feb 19, 2026
Reviewed Feb 19, 2026
Last updated Feb 19, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS score

Weaknesses

Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource. Learn more on MITRE.

CVE ID

No known CVE

GHSA ID

GHSA-p536-vvpp-9mc8

Source code

Credits

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