CVE-2026-77253: MCP Atlassian: Jira and Confluence attachment upload tools can read arbitrary server-local files

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% 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, Jira and Confluence attachment upload tools accept arbitrary local filesystem paths and send the selected bytes to Atlassian. In HTTP or multi-user deployments, a caller can cross the client-to-server filesystem boundary and disclose configuration, credentials, mounted secrets, or other files readable by the MCP process. The advisory traces the vulnerable input and processing flow through jira_upload_attachment, confluence_upload_attachment, file_path, and server-local filesystem, 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

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