CVE-2026-77255: MCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue
A critical Confused Deputy (Arbitrary File Read & Exfiltration) vulnerability in the Atlassian MCP server (Python) allows an AI agent to exfiltrate sensitive host files and environment secrets. By providing absolute system paths to the attachments parameter of the update_issue tool, an agent can force the privileged MCP process to read and upload any file it has access to—including its own environment variables and host configuration—directly to a Jira ticket.
References
- github.com/advisories/GHSA-2xj6-xx86-cwwc
- github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460
- github.com/sooperset/mcp-atlassian/pull/1448
- github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0
- github.com/sooperset/mcp-atlassian/security/advisories/GHSA-2xj6-xx86-cwwc
- nvd.nist.gov/vuln/detail/CVE-2026-77255
Code Behaviors & Features
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