Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the Jira update_issue attachments argument is converted into local paths and routed to the attachment upload implementation without workspace validation. A caller can make the MCP server read arbitrary local files and attach them to a Jira issue, using the server as a confused deputy to exfiltrate the contents. The advisory traces the vulnerable input and processing flow through jira update_issue, attachments, upload_attachment, and file_path, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
Published: 2026-09-22
Score: 8.6 High
EPSS: n/a
KEV: No
Impact: Confidential data exfiltration
Action: Apply Patch
AI Analysis

Impact

MCP Atlassian, a Model Context Protocol server for Atlassian products, contains a flaw in the JIRA update_issue attachment handling that allows a caller to supply a path that is translated into a local file system location without proper workspace validation. As a result, an attacker can cause the MCP server to read any file on the host and attach its contents to a JIRA issue, effectively exfiltrating confidential data. The vulnerability is a classic confused‑deputy scenario (CWE‑441) in which the server performs an action it is allowed to do but with untrusted arguments, leading to a loss of confidentiality. No impact on integrity or availability is described.

Affected Systems

The vulnerability affects the sooperset mcp-atlassian product, specifically all releases prior to version 0.22.0. Users running 0.21.x or earlier are susceptible; the issue is fixed in 0.22.0.

Risk and Exploitability

The flaw carries a CVSS score of 8.6, indicating high severity, and it is not currently listed in the CISA KEV catalog. The EPSS score is not available, but the description suggests that exploitation requires a valid remote call to the MCP server; therefore the attack vector is remote. An attacker with network access to the MCP server can construct a malicious attachments payload that points to a local file and trigger the read and upload process, thereby exfiltrating data with no additional privileges.

Generated by OpenCVE AI on September 22, 2026 at 19:52 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Update MCP Atlassian to version 0.22.0 or later
  • Enforce strict validation on the attachments argument to ensure it cannot reference local file system paths before processing
  • Monitor update_issue requests for abnormal attachment paths or unexpected file uploads

Generated by OpenCVE AI on September 22, 2026 at 19:52 UTC.

Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-2xj6-xx86-cwwc MCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue
History

Tue, 22 Sep 2026 20:15:00 +0000

Type Values Removed Values Added
First Time appeared Sooperset
Sooperset mcp-atlassian
Vendors & Products Sooperset
Sooperset mcp-atlassian

Tue, 22 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Description MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the Jira update_issue attachments argument is converted into local paths and routed to the attachment upload implementation without workspace validation. A caller can make the MCP server read arbitrary local files and attach them to a Jira issue, using the server as a confused deputy to exfiltrate the contents. The advisory traces the vulnerable input and processing flow through jira update_issue, attachments, upload_attachment, and file_path, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
Title MCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue
Weaknesses CWE-22
CWE-441
References
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N'}

Subscriptions

Sooperset Mcp-atlassian
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-22T18:29:20.167Z

Reserved: 2026-08-20T19:02:23.417Z

Link: CVE-2026-77255

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-22T19:16:49.850

Modified: 2026-09-22T19:16:49.850

Link: CVE-2026-77255

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-22T20:00:13Z

Weaknesses
  • CWE-22

    Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

  • CWE-441

    Unintended Proxy or Intermediary ('Confused Deputy')