CVE-2026-66421: OpenClaw — CRITICAL

OpenClaw Dashboard contains a stored cross-site scripting vulnerability that allows unauthenticated remote attackers to execute arbitrary JavaScript in the administrator's browser session by injecting HTML markup into agent transcript messages processed through the sessions API. Attackers can craft...

Full CISO analysis pending enrichment.

What systems are affected?

Package	Ecosystem	Vulnerable Range	Patched
OpenClaw	pip	—	No patch
4 dependents 37% patched ~3d to patch Full package profile →

Do you use OpenClaw? You're affected.

How severe is it?

CVSS 3.1

9.3 / 10

EPSS

N/A

Exploitation Status

No known exploitation

Sophistication

N/A

What is the attack surface?

AV Network

AC Low

PR None

UI Required

S Changed

C High

I High

A None

What should I do?

No patch available

Monitor for updates. Consider compensating controls or temporary mitigations.

Which compliance frameworks are affected?

Compliance analysis pending. Sign in for full compliance mapping when available.

Frequently Asked Questions

What is CVE-2026-66421?

OpenClaw Dashboard contains a stored cross-site scripting vulnerability that allows unauthenticated remote attackers to execute arbitrary JavaScript in the administrator's browser session by injecting HTML markup into agent transcript messages processed through the sessions API. Attackers can craft a message containing inline event handler payloads such as an img tag with an onerror attribute within the 60-character rendering budget, which is stored in the session transcript and interpolated unsanitized into innerHTML on the default landing page, allowing theft of session tokens and unauthorized calls to authenticated administrative endpoints including agent instruction file modification.

Is CVE-2026-66421 actively exploited?

No confirmed active exploitation of CVE-2026-66421 has been reported, but organizations should still patch proactively.

How to fix CVE-2026-66421?

No patch is currently available. Monitor vendor advisories for updates.

What is the CVSS score for CVE-2026-66421?

CVE-2026-66421 has a CVSS v3.1 base score of 9.3 (CRITICAL).

What are the technical details?

Original Advisory

OpenClaw Dashboard contains a stored cross-site scripting vulnerability that allows unauthenticated remote attackers to execute arbitrary JavaScript in the administrator's browser session by injecting HTML markup into agent transcript messages processed through the sessions API. Attackers can craft a message containing inline event handler payloads such as an img tag with an onerror attribute within the 60-character rendering budget, which is stored in the session transcript and interpolated unsanitized into innerHTML on the default landing page, allowing theft of session tokens and unauthorized calls to authenticated administrative endpoints including agent instruction file modification.

Weaknesses (CWE)

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') Primary CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CWE-79 — Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'): The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

[Architecture and Design] Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482]. Examples of libraries and frameworks that make it easier to generate properly encoded output include Microsoft's Anti-XSS library, the OWASP ESAPI Encoding module, and Apache Wicket.
[Implementation, Architecture and Design] Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages. Study all expected communication protocols and data representations to determine the required encoding strategies. For any data that will be output to another web page, especially any data that was received from external inputs, use the appropriate encoding on all non-alphanumeric characters. Parts of the same output document may require different encodings, which will vary depending on whether the output is in the: etc. Note that HTML Entity Encoding is only appropriate for the HTML body. Consult the XSS Prevention Cheat Sheet [REF-724] for more details on the types of encoding and escaping that are needed. HTML body Element attributes (such as src="XYZ") URIs JavaScript sections Casca

Source: MITRE CWE corpus.