Vulnerability · Published Aug 18, 2026 · Assigned by GitHub_M

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

High 8.7

In plain English

A high-severity cross-site scripting in kestra from kestra-io. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.7High

Exploit odds (30 days)0.4%top 62.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Maven	io.kestra:kestra	1.3.24	GHSA-34pm-923j-7wf8

Affected products (as reported)

Vendor	Product	Versions
kestra-io	kestra	< 1.3.24

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

References

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