What’s Vulnerable › Vulnerabilities

CVE-2026-77266: MCP Atlassian: Path traversal in upload_attachment allows arbitrary file read and exfiltration via MCP tool call

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-09-22 · updated 2026-09-28
• Weakness: CWE-22

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, upload_attachment accepts absolute paths and traversal sequences without constraining the resolved path to the server workspace. An MCP caller with attachment access can read a chosen server-local file and exfiltrate it through Jira or Confluence. The advisory traces the vulnerable input and processing flow through upload_attachment, file_path, and path traversal, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

Affected products

• sooperset mcp-atlassian: before 0.22.0 — fixed in 0.22.0

How to fix

Upgrade to a fixed version: sooperset mcp-atlassian 0.22.0. Check the vendor advisory for mitigations.

References

• https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460
• 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/security/advisories/GHSA-mfv2-4wvm-9pgp
• https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-mfv2-4wvm-9pgp

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