CVE-2026-77621: Vector: Arbitrary file write in the file sink via templated path (path traversal).
Vector is a high-performance observability data pipeline. From 0.10.0 until 0.57.0, the file sink renders its templated path from event fields and opens the result without confining it to an intended directory. When an untrusted source supplies an event field used by the path template, the value can contain an absolute path or parent-directory traversal, causing Vector to create parent directories and create or overwrite files outside the intended location with the Vector process privileges. The resulting file write can modify sensitive files and can lead to code execution when a scheduled task, authorization file, or subsequently executed script is targeted. This issue is fixed in version 0.57.0.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Vectorto a version that resolves this vulnerability.Fixed in 0.57.0
Event History
Frequently Asked Questions
What conditions are required to exploit this issue?
An attacker must be able to supply an untrusted event field that is referenced by a file sink path template. The attacker can then use an absolute path or parent-directory traversal in that field to direct writes outside the intended directory.
Which deployments are exposed?
Vector versions from 0.10.0 up to, but not including, 0.57.0 are affected when a file sink uses a templated path containing event-supplied data from an untrusted source. Deployments without such a path template are not described as exploitable by the available information.
What is the practical impact of a successful exploit?
The attacker can cause Vector to create directories and create or overwrite files with the privileges of the Vector process. This may enable modification of sensitive files and potential code execution if the target is a scheduled task, authorization file, or script that is later executed.
What is the remediation?
Upgrade Vector to version 0.57.0, which fixes the issue. If upgrading cannot happen immediately, avoid using untrusted event fields in file sink path templates.