MSRXCVE-2026-77248
CVE-2026-77248
MCP Atlassian: Unauthenticated arbitrary local file read via upload_attachment file_path, chained with missing auth on streamable-http transport
CVSS 3.1 · CNA
chance of exploitation in the next 30 days (EPSS; higher than 40% of CVEs)
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the streamable HTTP transport accepts requests without a user identity and falls back to operator credentials, while upload_attachment accepts an unrestricted file_path. An unauthenticated network caller can read files available to the MCP process, upload them to an attacker-selected Jira issue or Confluence page, and retrieve the contents. The advisory traces the vulnerable input and processing flow through streamable-http, UserTokenMiddleware, upload_attachment, file_path, and _get_fetcher, 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
Also known as: GHSA-cc5h-2pwp-pvcc, PYSEC-2026-4089
4 references (advisories, patches, write-ups)
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-cc5h-2pwp-pvcc · 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.