CVE-2026-77257

MCP Atlassian: HTTP upload tools accept arbitrary server-local file paths

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, HTTP-exposed Jira and Confluence upload tools pass a caller-provided file_path to local file operations without restricting it to the workspace. A remote MCP caller with tool access can cause the server to read sensitive local files and upload them as Atlassian attachments. The advisory traces the vulnerable input and processing flow through streamable-http, upload_attachment, and file_path, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

Affected

sooperset · mcp-atlassian

CVSS v4.0 GITHUB

8.3 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v4.0 GitHub

8.3 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

CVSS v3.1 NVD

6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS

0.39% chance of exploitation in the next 30 days, 31st percentile

Published

2026-09-22

Updated

2026-09-23

Proof-of-concept exploits (1)

• advisories/GHSA-mrq8-fv7v-hhjg

Security advisories

• sooperset/mcp-atlassian/security/advisories/GHSA-mrq8-fv7v-hhjg
• sooperset/mcp-atlassian/pull/1448

References

• CVE Record
• NVD entry