MSRXCVE-2026-77266
CVE-2026-77266
MCP Atlassian: Path traversal in upload_attachment allows arbitrary file read and exfiltration via MCP tool call
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, upload_attachment accepts absolute paths and traversal sequences without constraining the resolved path to the server workspace. An MCP caller with attachment access can read a chosen server-local file and exfiltrate it through Jira or Confluence. The advisory traces the vulnerable input and processing flow through upload_attachment, file_path, and path traversal, 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-mfv2-4wvm-9pgp, PYSEC-2026-4097
4 references (advisories, patches, write-ups)
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-mfv2-4wvm-9pgp · 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.