CVE-2026-77269: MCP Atlassian: Path traversal in upload_attachment allows arbitrary file read (incomplete fix for CVE-2026-27825)
The confluence_upload_attachment and confluence_upload_attachments MCP tools accept a file_path parameter and do not validate that the path is confined to an allowed directory before opening the file. An attacker who can call these tools can read any file accessible to the MCP server process (SSH keys, .env files, API credentials) and exfiltrate it by uploading it to Confluence.
Note: The Jira upload_attachment mixin method in jira/attachments.py has the same missing validation, but it is NOT registered as an MCP tool in servers/jira.py and is therefore not currently reachable via MCP. It should still be patched to prevent future exposure if Jira upload tools are added.
This is an incomplete fix for CVE-2026-27825. That CVE was patched by adding validate_safe_path() to download operations (v0.17.0). The same protection was not applied to upload operations.
References
- github.com/advisories/GHSA-h7wj-5v37-59r2
- github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460
- github.com/sooperset/mcp-atlassian/pull/1448
- github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0
- github.com/sooperset/mcp-atlassian/security/advisories/GHSA-h7wj-5v37-59r2
- nvd.nist.gov/vuln/detail/CVE-2026-77269
Code Behaviors & Features
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