CVE-2026-77246

HighCVSS 8.6/10Last modified Sep 28, 2026

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, an HTTP transport deployment with READ_ONLY_MODE=false accepts a request without an Authorization identity and permits attacker-controlled Atlassian service headers, including X-Atlassian-Confluence-Url, to select a public attacker hostname or one allowed by MCP_ALLOWED_URL_DOMAINS. A caller can then invoke confluence_upload_attachment or the Jira attachment variant in src/mcp_atlassian/jira/attachments.py with a server-local file_path and cause the MCP process to send the file to the selected attachment endpoint. This issue is fixed in version 0.22.0.

Metrics

CVSS 3.1 8.6/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Weakness enumeration

CWE-22CWE-200CWE-441

Affected software

No affected versions have been published.

Timeline

Published
Sep 22, 2026
Last modified
Sep 28, 2026
NVD status
Analyzed

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CVE-2026-77246: High severity, CVSS 8.6 | Vulnix