What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-18 · updated 2026-10-22
• Weakness: CWE-79

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.

Affected products

• kestra-io kestra: before 1.3.24

References

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

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