{"id":"CVE-2026-77250","published":"2026-09-22T18:17:17.720","lastModified":"2026-09-23T18:28:25.093","description":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, OAuthConfig writes a plaintext fallback file containing access and refresh tokens under the user's .mcp-atlassian directory using process-default permissions. On systems with a permissive umask, same-group or other local users and processes can read the persisted tokens and reuse the associated Atlassian access. The advisory traces the vulnerable input and processing flow through OAuthConfig._save_tokens, ~/.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.","cvssScore":6.1,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N","cwes":["CWE-312"],"vendors":[],"products":[],"references":[{"url":"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/pull/1448","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6","tags":[]}],"exploitRefs":[{"url":"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/pull/1448","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6","tags":[]},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6","tags":[]}],"hasPoc":true,"ai":null}