CVE-2026-77621 Vector: Arbitrary file write in the file sink via templated path (path traversal).
Attackers can write arbitrary files outside intended directories via templated paths, potentially leading to code execution or data modification.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-77621?
CVE-2026-77621 is a critical path traversal vulnerability in vectordotdev vector, published on 22 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-77621?
How do I fix CVE-2026-77621?
No fix has been published for CVE-2026-77621 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-77621 being exploited?
There is no known exploitation of CVE-2026-77621 in the wild and no public exploit code.
Sources
Also known as GHSA-6342-xwvw-c637.