CVE-2026-45807: Kestra: Path traversal via URL-encoded "%2E%2E" in execution and namespace file endpoints allows arbitrary file read

Severity: high (CVSS 7.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-26 · updated 2026-10-25
Weakness: CWE-22

Description

Kestra is an open-source, event-driven orchestration platform. Prior to 1.0.43 and 1.3.19, several Kestra API endpoints accept a kestra:// URI from the client and pass it through StorageInterface.parentTraversalGuard before reading the underlying file from the local storage backend. The guard only inspects the literal URI.toString(), so a URL-encoded .. written as %2E%2E slips through. The downstream code then calls URI.getPath(), which decodes %2E%2E back to .., and the resulting path is handed to Paths.get(...) without normalization. The OS resolves the .. segments at open(2) time, so an authenticated user with a single execution can read any file the Kestra process has access to on the host filesystem (/etc/passwd, mounted secrets, other tenants' execution outputs, etc.). This vulnerability is fixed in 1.0.43 and 1.3.19.

Affected products

kestra-io kestra: before 1.0.43; from 1.1.0 before 1.3.19 — fixed in 1.0.43, 1.3.19

How to fix

Upgrade to a fixed version: kestra-io kestra 1.0.43, 1.3.19. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-45807 or the next vulnerability affects your stack