---
id: "CVE-2026-12887"
kind: "vulnerability"
aliases: ["CVE-2026-12887"]
title: "Octopus Server: crafted NuGet package lets a deploy script escape its directory"
severity: "medium"
cvss: 5.1
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["dotnet", "nuget", "octopus-deploy", "package", "self-hosted"]
not_affected_if: ["managed-hosting", "no-package-upload-users"]
published_at: "2026-10-27T14:17:00+00:00"
first_seen_at: "2026-10-27T14:32:25+00:00"
updated_at: "2026-10-27T14:33:14+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-12887", "first_seen_at": "2026-10-27T14:32:25+00:00"}]
---

# Octopus Server: crafted NuGet package lets a deploy script escape its directory

A user who is allowed to upload NuGet packages to Octopus Server can craft one that makes a deployment script step run outside its parent directory. The sources do not say what files or hosts are then reachable.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Octopus Server version against the affected range in the NVD entry (https://nvd.nist.gov/vuln/detail/CVE-2026-12887)
- Review which users hold permission to upload packages to the built-in NuGet feed
- unknown for any further check, since the sources do not say

## Fix

- Move Octopus Server to a version that fixes CVE-2026-12887; the sources do not name it, so check the vendor advisory
- Restrict package upload permission to trusted users until patched

## Timeline

- 2026-10-27T14:32:25+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-12887

## From the sources

In affected versions of Octopus Server, a user with permission to upload a malicious nuget package is able to deploy a script step so the script executes outside of the parent directory.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_