MSRXCVE-2026-77270
CVE-2026-77270
MCP Atlassian: Arbitrary File Read via Upload Attachment Tools
CVSS 3.1 · CNA
chance of exploitation in the next 30 days (EPSS; higher than 42% of CVEs)
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.
Scores
Affected packages and fixed versions
| Package | Ecosystem | Fixed in |
|---|---|---|
| mcp-atlassian | PyPI | 0.22.0 |
Affected products
- sooperset mcp-atlassian: < 0.22.0
Weakness: CWE-22
Also known as: GHSA-f26r-j276-ggg4, PYSEC-2026-4090
4 references (advisories, patches, write-ups)
- 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
Sources: CVE.org, OSV.dev, FIRST EPSS. Missing ones did not answer or have no record yet.