---
title: "CVE-2026-77271: MCP Atlassian - Code Injection"
description: "MCP Atlassian < 0.22.0 contains a code injection vulnerability caused by insecure default base directory in validate_safe_path allowing attacker-selected writes in working directory, letting attackers achieve code execution when the application imports the modified module, exploit requires ability to write files in working directory."
url: https://panop.io/threat-heartbeat/CVE-2026-77271/
---

# CVE-2026-77271 MCP Atlassian - Code Injection

MCP Atlassian < 0.22.0 contains a code injection vulnerability caused by insecure default base directory in validate\_safe\_path allowing attacker-selected writes in working directory, letting attackers achieve code execution when the application imports the modified module, exploit requires ability to write files in working directory.

CVSS base score 8.8 /10

High

CISA KEV

Not listed

Public exploit

Proof of concept available

EPSS

0.53% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-77271)

## Details

Type

Code Injection

Impact

Remote Code Execution

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Published

22 September 2026

Updated

15 October 2026

Weakness

[CWE-22](https://cwe.mitre.org/data/definitions/22.html)

## Vendor fix

Upgrade to version 0.22.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-77271](https://nvd.nist.gov/vuln/detail/CVE-2026-77271)
- [https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460](https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460)
- [https://github.com/sooperset/mcp-atlassian/pull/1448](https://github.com/sooperset/mcp-atlassian/pull/1448)
- [https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0](https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0)
- [https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6vmq-24h2-pj7j](https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6vmq-24h2-pj7j)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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