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TI-2026-40304 Aliases CVE-2026-55839GHSA-34pm-923j-7wf8

Kestra: Stored XSS via custom Markdown [[link]] attribute injection

Priority MEDIUM 40CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-79.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0043 37th percentileScored 2026-11-07
Fix Fixed kestra (kestra-io): 1.3.24io.kestra:kestra (Maven): 1.3.24

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Kestrakestrabefore 1.3.241.3.24Patch availableCNA
—io.kestra:kestra (Maven)before 1.3.241.3.24Patch availableGHSA-34pm-923j-7wf8
  • kestra VendorKestra Affected before 1.3.24 Fixed in 1.3.24 Patch available CNA
  • io.kestra:kestra (Maven) Vendor— Affected before 1.3.24 Fixed in 1.3.24 Patch available GHSA-34pm-923j-7wf8

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:kestra:kestra:*:*:*:*:*:*:*:*——Kestra
  • cpe:2.3:a:kestra:kestra:*:*:*:*:*:*:*:* Versions — — ·Kestra

Remediation

  • Fix · CNA kestra (kestra-io) Fixed in 1.3.24
  • Fix · GHSA-34pm-923j-7wf8 io.kestra:kestra (Maven) Fixed in 1.3.24 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55839
  2. 2026-10-03 Alias added: GHSA-34pm-923j-7wf8

References

Other 5

  • TI-2026-36769 Kestra: Unauthenticated Remote Code Execution via Authentication Bypass in `AuthenticationFilter` KEVCVSS 3.1CRITICAL 10.0
  • TI-2026-38637 Kestra: Unauthenticated RCE via /configs path-suffix auth-filter bypass CVSS 3.1CRITICAL 10.0
  • TI-2026-28138 Kestra v1.3.3 and before is vulnerable to SQL Injection. CVSS 3.1CRITICAL 9.8
  • TI-2026-51384 Kestra: SSRF via Pebble http() function allows unauthenticated access to internal services & cloud metadata CVSS 3.1HIGH 8.6
  • TI-2026-26858 Kestra: Remote Code Execution via SQL Injection CVSS 3.1CRITICAL 10.0
  • TI-2026-39775 Kestra BasicAuth Password Stored as SHA-512 Enables Offline Brute-Force Attack CVSS 3.1HIGH 8.7
See all 15 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences