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.
The record classifies CVE-2026-66421 under weakness class CWE-79. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first, and has high impact on confidentiality, integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 67 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.3 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N - CVSS v4.0 base score
- 8.8
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N - EPSS (FIRST)
- 0.3% probability of exploitation in the next 30 days, higher than 28.9% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 5.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-07-30, last modified 2026-07-31
Is CVE-2026-66421 being exploited?
It currently carries a trending score of 36 in the Threadlinqs vulnerability feed.
Affected products and versions
- tugcantopaloglu: openclaw-dashboard
How to fix CVE-2026-66421
No vendor patch reference has been recorded for CVE-2026-66421 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-66421
No threat campaign in the Threadlinqs corpus currently references CVE-2026-66421, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.