CVE-2026-77268

Medium

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the OAuth fallback token directory and JSON file are created without explicit owner-only modes. Local users or processes with access through the resulting group or world permission bits can read access and refresh tokens and reuse the associated Atlassian session. The advisory traces the vulnerable input and processing flow through ~/.mcp-atlassian, oauth-<client_id>.json, access_token, and refresh_token, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

SeverityMedium

CVSS5.5

Exploit probability—

ProductMcp-atlassian

PublishedSep 22, 2026

First seenSep 22, 2026

Weakness typeCWE-732CWE-732

How to fix

Update

mcp-atlassian0.22.0 or later
mcp-atlassian mcp_atlassian0.22.0 or later

Affected products

Product	Affected versions	Fixed in
mcp-atlassianPyPI	v < 0.22.0	0.22.0
mcp-atlassian mcp_atlassian	v < 0.22.0	0.22.0

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