CVE-2026-66421

CRITICALPre-NVD 9.39.3—
EchelonGraph scoreHIGH confidence

Score 9.3 from GitHub Security Advisory (severity: HIGH) published 2026-07-31. a secondary CVSS source baseline 9.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
9.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.3Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.3
EG Score
9.3(high)
EG Risk
58(Track)
EG Risk 58/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity93% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
30%
KEV
Not listed

Published

July 30, 2026

Last Modified

July 31, 2026

Advisory Details (3)

Auto-updated Aug 1, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

GitHub - theopaid/Stored-Cross-Site-Scripting-Via-Agent-Messages-Leading-To-Session-Token-Theft-openclaw-dashboard-: Security Advisory: Stored Cross-Site Scripting Via Agent Messages Leading To Session Token Theft (openclaw-dashboard) · GitHub

https://github.com/theopaid/Stored-Cross-Site-Scripting-Via-Agent-Messages-Leading-To-Session-Token-Theft-openclaw-dashboard-
generic

OpenClaw Dashboard Stored XSS via lastMessage Session Field | Advisories | VulnCheck

https://www.vulncheck.com/advisories/openclaw-dashboard-stored-xss-via-lastmessage-session-field
generic

GitHub - tugcantopaloglu/openclaw-dashboard: 🔐 Secure, real-time monitoring dashboard for OpenClaw AI agents. Auth, TOTP MFA, cost tracking, live feed, memory browser and more. · GitHub

https://github.com/tugcantopaloglu/openclaw-dashboard

Vendor Advisories for CVE-2026-66421(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 56× in last 7d / 174× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 174 total refreshes for this CVE.

  1. 2026-08-20 23:06 UTCEG score recompute
  2. 2026-08-20 23:06 UTCGHSA enrichment
  3. 2026-08-20 22:56 UTCEPSS rescore
  4. 2026-08-20 19:10 UTCGHSA enrichment
  5. 2026-08-20 15:14 UTCGHSA enrichment
  6. 2026-08-20 11:18 UTCGHSA enrichment
  7. 2026-08-20 07:21 UTCGHSA enrichment
  8. 2026-08-20 03:25 UTCGHSA enrichment
  9. 2026-08-19 23:25 UTCGHSA enrichment
  10. 2026-08-19 19:28 UTCEG score recompute
  11. 2026-08-19 19:28 UTCGHSA enrichment
  12. 2026-08-19 17:04 UTCEPSS rescore
  13. 2026-08-19 14:40 UTCGHSA enrichment
  14. 2026-08-19 10:25 UTCGHSA enrichment
  15. 2026-08-19 06:24 UTCGHSA enrichment
  16. 2026-08-19 02:20 UTCGHSA enrichment
  17. 2026-08-18 22:24 UTCGHSA enrichment
  18. 2026-08-18 18:27 UTCEG score recompute
  19. 2026-08-18 18:27 UTCGHSA enrichment
  20. 2026-08-18 13:48 UTCEPSS rescore
  21. 2026-08-18 13:02 UTCGHSA enrichment
  22. 2026-08-18 08:57 UTCGHSA enrichment
  23. 2026-08-18 04:58 UTCGHSA enrichment
  24. 2026-08-18 01:01 UTCGHSA enrichment
  25. 2026-08-17 20:32 UTCGHSA enrichment
Show 75 more
  1. 2026-08-17 16:33 UTCEG score recompute
  2. 2026-08-17 16:33 UTCGHSA enrichment
  3. 2026-08-17 13:47 UTCEPSS rescore
  4. 2026-08-17 12:23 UTCGHSA enrichment
  5. 2026-08-17 08:25 UTCGHSA enrichment
  6. 2026-08-17 04:29 UTCGHSA enrichment
  7. 2026-08-17 00:33 UTCGHSA enrichment
  8. 2026-08-16 20:37 UTCGHSA enrichment
  9. 2026-08-16 16:40 UTCEG score recompute
  10. 2026-08-16 16:40 UTCGHSA enrichment
  11. 2026-08-16 14:56 UTCEPSS rescore
  12. 2026-08-16 12:43 UTCGHSA enrichment
  13. 2026-08-16 08:46 UTCGHSA enrichment
  14. 2026-08-16 04:50 UTCEG score recompute
  15. 2026-08-16 04:50 UTCGHSA enrichment
  16. 2026-08-16 00:54 UTCGHSA enrichment
  17. 2026-08-15 20:58 UTCGHSA enrichment
  18. 2026-08-15 17:02 UTCGHSA enrichment
  19. 2026-08-15 13:06 UTCGHSA enrichment
  20. 2026-08-15 09:10 UTCGHSA enrichment
  21. 2026-08-15 05:14 UTCEG score recompute
  22. 2026-08-15 05:14 UTCGHSA enrichment
  23. 2026-08-15 01:30 UTCEPSS rescore
  24. 2026-08-15 01:17 UTCGHSA enrichment
  25. 2026-08-14 21:21 UTCGHSA enrichment
  26. 2026-08-14 17:22 UTCGHSA enrichment
  27. 2026-08-14 13:21 UTCGHSA enrichment
  28. 2026-08-14 09:25 UTCGHSA enrichment
  29. 2026-08-14 05:29 UTCGHSA enrichment
  30. 2026-08-14 01:33 UTCEG score recompute
  31. 2026-08-14 01:33 UTCGHSA enrichment
  32. 2026-08-13 22:00 UTCEPSS rescore
  33. 2026-08-13 21:36 UTCGHSA enrichment
  34. 2026-08-13 17:40 UTCGHSA enrichment
  35. 2026-08-13 13:40 UTCGHSA enrichment
  36. 2026-08-13 09:44 UTCGHSA enrichment
  37. 2026-08-13 05:48 UTCGHSA enrichment
  38. 2026-08-13 01:51 UTCGHSA enrichment
  39. 2026-08-12 21:55 UTCGHSA enrichment
  40. 2026-08-12 17:59 UTCGHSA enrichment
  41. 2026-08-12 14:03 UTCEG score recompute
  42. 2026-08-12 14:03 UTCGHSA enrichment
  43. 2026-08-12 13:51 UTCEPSS rescore
  44. 2026-08-12 10:04 UTCGHSA enrichment
  45. 2026-08-12 06:07 UTCGHSA enrichment
  46. 2026-08-12 02:10 UTCGHSA enrichment
  47. 2026-08-11 22:13 UTCGHSA enrichment
  48. 2026-08-11 18:17 UTCGHSA enrichment
  49. 2026-08-11 14:09 UTCEG score recompute
  50. 2026-08-11 14:09 UTCGHSA enrichment
  51. 2026-08-11 10:12 UTCGHSA enrichment
  52. 2026-08-11 06:16 UTCGHSA enrichment
  53. 2026-08-11 02:20 UTCEG score recompute
  54. 2026-08-11 02:20 UTCGHSA enrichment
  55. 2026-08-11 00:00 UTCEPSS rescore
  56. 2026-08-10 22:24 UTCGHSA enrichment
  57. 2026-08-10 18:28 UTCGHSA enrichment
  58. 2026-08-10 14:32 UTCGHSA enrichment
  59. 2026-08-10 10:35 UTCGHSA enrichment
  60. 2026-08-10 06:37 UTCGHSA enrichment
  61. 2026-08-10 02:41 UTCGHSA enrichment
  62. 2026-08-09 22:44 UTCGHSA enrichment
  63. 2026-08-09 18:48 UTCGHSA enrichment
  64. 2026-08-09 14:52 UTCEG score recompute
  65. 2026-08-09 14:52 UTCGHSA enrichment
  66. 2026-08-09 13:47 UTCEPSS rescore
  67. 2026-08-09 10:55 UTCGHSA enrichment
  68. 2026-08-09 06:59 UTCGHSA enrichment
  69. 2026-08-09 03:03 UTCGHSA enrichment
  70. 2026-08-08 23:07 UTCGHSA enrichment
  71. 2026-08-08 19:11 UTCEG score recompute
  72. 2026-08-08 19:11 UTCGHSA enrichment
  73. 2026-08-08 16:37 UTCEPSS rescore
  74. 2026-08-08 15:15 UTCGHSA enrichment
  75. 2026-08-08 11:18 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66421?
CVE-2026-66421 is a critical vulnerability published on July 30, 2026. 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…
When was CVE-2026-66421 disclosed?
CVE-2026-66421 was first published in the National Vulnerability Database on July 30, 2026, with the most recent update on July 31, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66421 actively exploited?
CVE-2026-66421 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 70.4% of all scored CVEs.
What is the CVSS score of CVE-2026-66421?
CVE-2026-66421 has a CVSS v3 base score of 9.3 (NVD).
How do I remediate CVE-2026-66421?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66421, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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