Vulnerability · Published Sep 22, 2026 · Assigned by GitHub_M
CVE-2026-77270MCP Atlassian: Arbitrary File Read via Upload Attachment Tools
Medium 6.5
In plain English
A medium-severity path traversal in mcp-atlassian from sooperset. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the Jira and Confluence attachment upload tools treat caller-controlled file_path values as trusted server-local paths. The server opens the selected file and uploads it to an Atlassian issue or page, allowing an MCP caller with upload access to disclose any file readable by the server process. The advisory traces the vulnerable input and processing flow through confluence_upload_attachment, jira_upload_attachment, file_path, and open(file_path, "rb"), which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | mcp-atlassian | 0.22.0 | GHSA-f26r-j276-ggg4 |
| PyPI | mcp-atlassian | 0.22.0 | PYSEC-2026-4090 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| sooperset | mcp-atlassian | < 0.22.0 |
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
References
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-f26r-j276-ggg4 x_refsource_CONFIRM
- https://github.com/sooperset/mcp-atlassian/pull/1448 x_refsource_MISC
- https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 x_refsource_MISC
- https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 x_refsource_MISC