Tracking: CVE-2026-77270
Severity: Medium
Who is affected
mcp-atlassian before 0.22.0, where an authenticated MCP caller or a manipulated agent can invoke affected attachment operations.
How the attack works
Jira and Confluence upload paths accept local filenames without consistently applying the server's safe-path validation. In Jira, the reported route includes the attachments parameter to update_issue.
A caller can make the server open a file outside the intended directory and transfer its contents as an attachment. The server's own filesystem access becomes available through an operation that appears to be an ordinary issue or page update.
What to do
- Upgrade to 0.22.0 or later and verify the running package version.
- Review Jira issue updates and Confluence attachments alongside MCP request logs. Investigate local paths outside the configured project or allowed directory.
- Restrict readable mounts and account privileges. If credentials were attached, revoke them at their source as well as removing the attachment.
Scope and limits
This report overlaps other mcp-atlassian upload advisories in the collection. Use the shared package fix while retaining each identifier for tracking.