kestra: Improper Limitation of a Pathname to a Restricted Directory
CVE-2026-49984 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in kestra from Kestra-io, with a CVSS 3.1 base score of 7.7 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected kestra versions: < 1.0.45; >= 1.1.0, < 1.3.23. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.57% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of kestra you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N. Scored by CNA (github.com).
Official description
Kestra is an open-source, event-driven orchestration platform. Prior to 1.0.45 and 1.3.23, the local internal-storage backend validates user-supplied paths for .. traversal before it converts Windows-style backslashes to forward slashes. An attacker can therefore smuggle a traversal sequence past the guard using backslashes (..\..\..\); the guard sees a harmless string, and the path is only rewritten to ../../../ after validation, immediately before the file is opened. Any authenticated user who can view an execution (the lowest-privilege role) can call GET /api/v1/{tenant}/executions/{executionId}/file?path=… and read any file on the server filesystem readable by the Kestra process, outside the storage sandbox and across every tenant and namespace. This includes the embedded H2 database (all flows, all users, all stored secrets), internal storage of every other tenant/namespace, mounted secret files, and the process environment (/proc/self/environ) which contains configured database and secret-backend credentials. It is a complete breach of Kestra's storage isolation and multi-tenancy boundary. This vulnerability is fixed in 1.0.45 and 1.3.23.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in kestra
- 8.7 High severity
- 8.6 High severity
- 7.5 High severity
- 8.7 High severity
- 10.0 Critical severity
- 10.0 Critical severity
Kestra OSS OS Command Injection Exploited
Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities
- 7.7 High severity
- 9.6 Critical severity
- 8.6 High severity
- 8.1 High severity
- 7.5 High severity
- 9.1 Critical severity
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