Vulnerability Intelligence Report
Kestra: Stored XSS via custom Markdown [[link]] attribute injection
CVE-2026-55839
Kestra is an open-source, event-driven orchestration platform. Prior to 1.3.24, Kestra's custom Markdown parser in ui/src/utils/markdown_plugins/link.ts allows a user with permission to create or update a Flow description to inject JavaScript event-handler attributes through the custom [[link]] syntax, causing stored cross-site scripting when another user opens the description or information panel in the Flow list. This issue is fixed in version 1.3.24.
Cross-Site Scripting (XSS)
No Active Exploit Signals
CVSS Base Score
8.7
HIGH
Exploitability:2.3
Impact Score:5.8
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-79 ↗CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| kestra-io | kestra | < 1.3.24 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
GitHub Advisory
Vulnerability Class
Cross-Site Scripting (XSS)
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | GitHub, Inc. · Vendor · USA |
| Reserved | 2026-06-17T16:29:38 |
| Published | 2026-08-18T15:27:18 |
| Last Updated | 2026-08-18T17:46:37 |
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