CVE-2026-77258
A permitted Confluence MCP caller can upload the file as an attachment and disclose data readable by the server process.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.37%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, upload_attachment in src/mcp_atlassian/confluence/attachments.py accepts a caller-controlled file_path and opens the selected server-local file without restricting it to the workspace. A permitted Confluence MCP caller can upload the file as an attachment and disclose data readable by the server process. This issue is fixed in version 0.22.0.
- CVSS 3.1
- 7.7 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
- EPSS
- 0.37% probability · 31th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-22
- Affected
- mcp-atlassian/mcp atlassian
- Source
- security-advisories@github.com
EPSS moved from 0.5% on 23 September 2026 to 0.4% on 26 October 2026.
References
- https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460Patch
- https://github.com/sooperset/mcp-atlassian/pull/1448Issue Tracking, Patch
- https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0Release Notes
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-93xw-j965-9mx3Exploit, Vendor Advisory
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-93xw-j965-9mx3Exploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.