{"id":"CVE-2026-77266","title":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira)","summary":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, upload_attachment accepts absolute paths and traversal sequences without constraining the resolved path to the server w…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-22"],"vendor":"mcp-atlassian","product":"mcp-atlassian","affected":["mcp-atlassian < 0.22.0"],"patched":["mcp-atlassian 0.22.0"],"published":"2026-09-22","updated":"2026-09-23","sourceUpdated":"2026-09-23T18:12:04.247","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-77266","references":[{"url":"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460","label":"security-advisories@github.com"},{"url":"https://github.com/sooperset/mcp-atlassian/pull/1448","label":"security-advisories@github.com"},{"url":"https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0","label":"security-advisories@github.com"},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-mfv2-4wvm-9pgp","label":"security-advisories@github.com"},{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-mfv2-4wvm-9pgp","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://github.com/advisories/GHSA-mfv2-4wvm-9pgp"}],"tags":["nvd","ghsa","pip","cve.org","exploit-available"],"epss":0.00481,"epssPercentile":0.40617,"aliases":["GHSA-mfv2-4wvm-9pgp"],"ecosystem":"pip","exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-22T19:06:07.798996Z"},"ingestedAt":"2026-09-22T19:09:10.009Z","slug":"CVE-2026-77266","body":"## Overview\n\nMCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, upload_attachment accepts absolute paths and traversal sequences without constraining the resolved path to the server workspace. An MCP caller with attachment access can read a chosen server-local file and exfiltrate it through Jira or Confluence. The advisory traces the vulnerable input and processing flow through upload_attachment, file_path, and path traversal, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-77266)\n\nAffected packages:\n\n- `mcp-atlassian < 0.22.0`\n\nPatched in:\n\n- `mcp-atlassian 0.22.0`\n\nSource: https://github.com/advisories/GHSA-mfv2-4wvm-9pgp","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":209363,"id":"CVE-2026-77266","ts":1790107888715,"field":"exploit_available","old":"false","new":"true"}]}