CVE-2026-77621 vectordotdev CVE debrief

Who should care

Defenders responsible for Vector deployments, security teams, and developers using Vector in their applications should assess exposure and prioritize remediation. This includes reviewing system logs for signs of potential exploitation, ensuring that all Vector deployments are up-to-date and patched, and reviewing and updating incident response plans to account for this vulnerability. Additionally, operators of affected systems, platform administrators, and

Why it matters

CVE-2026-77621 is a critical vulnerability in Vector that allows for arbitrary file writes and potential code execution. Defenders should prioritize remediation by upgrading to version 0.57.0 or later and restrict event fields used in file sink path templates.

• Potential code execution through targeted scheduled tasks or authorization files
• Modification of sensitive files
• Elevation of privileges through file system manipulation
• Possible disruption of system operations through file overwrites

Technical summary

The file sink in Vector, a high-performance observability data pipeline, renders its templated path from event fields and opens the result without confining it to an intended directory. This allows an attacker to manipulate the path template and write to arbitrary files on the system, potentially leading to sensitive file modification and code execution. The vulnerability is fixed in version 0.57.0. Affected deployments should be upgraded immediately and event fields used in file sink path templates should be restricted to prevent exploitation.

Defensive priority

High

Recommended defensive actions

• Upgrade Vector to version 0.57.0 or later
• Review and restrict event fields used in file sink path templates
• Monitor Vector deployments for suspicious activity
• Implement additional security controls to prevent exploitation
• Conduct a thorough review of system logs for signs of potential exploitation
• Ensure that all Vector deployments are up-to-date and patched
• Review and update incident response plans to account for this vulnerability

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, its impact, and the fixed version. Multiple source references from GitHub are available, including commits, pull requests, and a security advisory.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.