{"id":"CVE-2026-77267","aliases":["EUVD-2026-84621","GHSA-5wf4-jqxh-8gm3","PYSEC-2026-4084"],"status":"published","title":"mcp-atlassian has an incomplete SSRF remediation","description":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination, bypassing the incomplete CVE-2026-27826 remediation. This issue is fixed in version 0.22.0.","severity":{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0032,"percentile":0.25269,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-918"],"published":"2026-09-22T17:52:25Z","modified":"2026-10-28T02:31:10Z","fixes":[{"ecosystem":"PyPI","package":"mcp-atlassian","fixed_in":["0.22.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"mcp-atlassian","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.22.0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"mcp-atlassian","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.22.0"}]}],"versions":["0.1.1","0.1.10","0.1.11","0.1.12","0.1.13","0.1.14","0.1.15","0.1.16","0.1.2","0.1.3","0.1.4","0.1.6","0.1.7","0.1.8","0.1.9","0.10.0","0.10.1","0.10.2","0.10.3","0.10.4","0.10.5","0.10.6","0.11.0","0.11.1","0.11.10","0.11.11","0.11.12","0.11.2","0.11.2a2","0.11.3","0.11.4","0.11.5","0.11.6","0.11.7","0.11.8","0.11.9","0.12.0","0.13.0","0.13.1","0.14.0","0.14.1","0.14.2","0.14.3","0.15.0","0.16.0","0.16.1","0.17.0","0.18.0","0.18.1","0.19.0","0.2.0","0.2.1","0.2.2","0.2.3","0.2.4","0.2.5","0.2.6","0.20.0","0.20.1","0.21.0","0.21.1","0.3.0","0.3.1","0.4.0","0.5.0","0.6.0","0.6.1","0.6.2","0.6.3","0.6.4","0.6.5","0.7.0","0.7.1","0.8.0","0.8.1","0.8.2","0.8.3","0.8.4","0.9.0"]},{"source":"osv","ecosystem":"PyPI","package":"mcp-atlassian","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.22.0"}]}],"versions":["0.1.1","0.1.10","0.1.11","0.1.12","0.1.13","0.1.14","0.1.15","0.1.16","0.1.2","0.1.3","0.1.4","0.1.6","0.1.7","0.1.8","0.1.9","0.10.0","0.10.1","0.10.2","0.10.3","0.10.4","0.10.5","0.10.6","0.11.0","0.11.1","0.11.10","0.11.11","0.11.12","0.11.2","0.11.2a2","0.11.3","0.11.4","0.11.5","0.11.6","0.11.7","0.11.8","0.11.9","0.12.0","0.13.0","0.13.1","0.14.0","0.14.1","0.14.2","0.14.3","0.15.0","0.16.0","0.16.1","0.17.0","0.18.0","0.18.1","0.19.0","0.2.0","0.2.1","0.2.2","0.2.3","0.2.4","0.2.5","0.2.6","0.20.0","0.20.1","0.21.0","0.21.1","0.3.0","0.3.1","0.4.0","0.5.0","0.6.0","0.6.1","0.6.2","0.6.3","0.6.4","0.6.5","0.7.0","0.7.1","0.8.0","0.8.1","0.8.2","0.8.3","0.8.4","0.9.0"]}],"products":[{"vendor":"mcp-atlassian","product":"mcp_atlassian"},{"vendor":"sooperset","product":"mcp-atlassian"}],"references":[{"url":"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-5wf4-jqxh-8gm3","tags":["x_refsource_CONFIRM","exploit","Exploit","Vendor Advisory","advisory","web"]},{"url":"https://github.com/sooperset/mcp-atlassian/pull/1448","tags":["x_refsource_MISC","Issue Tracking","Patch","fix","web"]},{"url":"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460","tags":["x_refsource_MISC","Patch","fix","web"]},{"url":"https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-77267","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-5wf4-jqxh-8gm3","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77267.json","tags":["advisory"]},{"url":"https://github.com/sooperset/mcp-atlassian","tags":["package"]},{"url":"https://pypi.org/project/mcp-atlassian","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-77267","title":"mcp-atlassian has an incomplete SSRF remediation","description":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination, bypassing the incomplete CVE-2026-27826 remediation. This issue is fixed in version 0.22.0.","status":"published","published":"2026-09-22T17:52:25.73Z","modified":"2026-09-28T17:18:50.679Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:20:15.712761Z"}],"euvd":[{"id":"EUVD-2026-84621","description":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination, bypassing the incomplete CVE-2026-27826 remediation. This issue is fixed in version 0.22.0.","status":"published","published":"2026-09-22T17:52:25Z","modified":"2026-09-28T17:18:50Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T17:27:53.091489Z"}],"ghsa":[{"id":"GHSA-5wf4-jqxh-8gm3","title":"mcp-atlassian has an incomplete SSRF remediation","description":"### Summary\n\nThe `UserTokenMiddleware` extracts URLs from `X-Atlassian-Jira-Url` and `X-Atlassian-Confluence-Url` HTTP headers and passes them directly to API client constructors without any SSRF validation.\n\n### Affected Package\n\n- **Ecosystem:** PyPI\n- **Package:** mcp-atlassian\n- **Affected versions:** all versions before fix commit 5cd697dfce91\n- **Patched versions:** \u003e= commit 5cd697dfce91\n\n### Details\n\nIn `main.py`, `_process_authentication_headers()` extracts URLs from ASGI headers without validation. In `dependencies.py`, `get_jira_fetcher()` creates `JiraConfig` with `url=jira_url_header` directly. There is no `validate_url` call, no IP range check, no hostname validation.\n\nThe fix adds URL validation to some paths but the header-based URL extraction in `_process_authentication_headers()` still passes raw URLs through. The derived config objects use the header URL directly and the fetcher makes HTTP requests to that URL.\n\n### PoC\n\n```python\njira_url_header = headers.get(b\"x-atlassian-jira-url\")\njira_url_str = jira_url_header.decode(\"latin-1\") if jira_url_header else None\nservice_headers[\"X-Atlassian-Jira-Url\"] = jira_url_str\n```\n\n**Steps to reproduce:**\n1. `git clone https://github.com/sooperset/mcp-atlassian /tmp/mcp-atlassian_test`\n2. `cd /tmp/mcp-atlassian_test \u0026\u0026 git checkout 5cd697dfce91~1`\n3. `pip install -e .`\n4. `python3 poc.py`\n\n**Expected output:**\n```\nVULNERABILITY CONFIRMED\nUser-supplied URLs from HTTP headers passed directly to JiraConfig/JiraFetcher with no SSRF validation\n```\n\n### Impact\n\nAn attacker can set `X-Atlassian-Jira-Url: http://169.254.169.254/latest/meta-data/` to access AWS instance metadata, or target any internal service. The server makes authenticated HTTP requests to the attacker-specified URL.\n\n### Suggested Remediation\n\nValidate all user-supplied URLs against an allowlist of permitted hostnames or reject private/loopback/link-local IP ranges. Consider requiring server-side configuration of allowed Atlassian instance URLs.","status":"published","published":"2026-09-22T20:36:17Z","modified":"2026-09-22T20:36:18Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N","level":"high"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:41:20.575159Z"}],"nvd":[{"id":"CVE-2026-77267","description":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination, bypassing the incomplete CVE-2026-27826 remediation. This issue is fixed in version 0.22.0.","status":"published","published":"2026-09-22T18:17:18.803Z","modified":"2026-09-29T18:59:56.113Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:12:50.368368Z"}],"osv":[{"id":"CVE-2026-77267","title":"mcp-atlassian has an incomplete SSRF remediation","description":"MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination, bypassing the incomplete CVE-2026-27826 remediation. This issue is fixed in version 0.22.0.","status":"published","published":"2026-09-22T17:52:25.73Z","modified":"2026-10-28T02:31:10.687759379Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N","level":"high"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:45:17.102988Z"},{"id":"GHSA-5wf4-jqxh-8gm3","title":"mcp-atlassian has an incomplete SSRF remediation","description":"### Summary\n\nThe `UserTokenMiddleware` extracts URLs from `X-Atlassian-Jira-Url` and `X-Atlassian-Confluence-Url` HTTP headers and passes them directly to API client constructors without any SSRF validation.\n\n### Affected Package\n\n- **Ecosystem:** PyPI\n- **Package:** mcp-atlassian\n- **Affected versions:** all versions before fix commit 5cd697dfce91\n- **Patched versions:** \u003e= commit 5cd697dfce91\n\n### Details\n\nIn `main.py`, `_process_authentication_headers()` extracts URLs from ASGI headers without validation. In `dependencies.py`, `get_jira_fetcher()` creates `JiraConfig` with `url=jira_url_header` directly. There is no `validate_url` call, no IP range check, no hostname validation.\n\nThe fix adds URL validation to some paths but the header-based URL extraction in `_process_authentication_headers()` still passes raw URLs through. The derived config objects use the header URL directly and the fetcher makes HTTP requests to that URL.\n\n### PoC\n\n```python\njira_url_header = headers.get(b\"x-atlassian-jira-url\")\njira_url_str = jira_url_header.decode(\"latin-1\") if jira_url_header else None\nservice_headers[\"X-Atlassian-Jira-Url\"] = jira_url_str\n```\n\n**Steps to reproduce:**\n1. `git clone https://github.com/sooperset/mcp-atlassian /tmp/mcp-atlassian_test`\n2. `cd /tmp/mcp-atlassian_test \u0026\u0026 git checkout 5cd697dfce91~1`\n3. `pip install -e .`\n4. `python3 poc.py`\n\n**Expected output:**\n```\nVULNERABILITY CONFIRMED\nUser-supplied URLs from HTTP headers passed directly to JiraConfig/JiraFetcher with no SSRF validation\n```\n\n### Impact\n\nAn attacker can set `X-Atlassian-Jira-Url: http://169.254.169.254/latest/meta-data/` to access AWS instance metadata, or target any internal service. The server makes authenticated HTTP requests to the attacker-specified URL.\n\n### Suggested Remediation\n\nValidate all user-supplied URLs against an allowlist of permitted hostnames or reject private/loopback/link-local IP ranges. Consider requiring server-side configuration of allowed Atlassian instance URLs.","status":"published","published":"2026-09-22T20:36:17Z","modified":"2026-10-01T17:56:07.799502598Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N","level":"high"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:46:38.911014Z"},{"id":"PYSEC-2026-4084","title":"mcp-atlassian has an incomplete SSRF remediation","description":"### Summary\n\nThe `UserTokenMiddleware` extracts URLs from `X-Atlassian-Jira-Url` and `X-Atlassian-Confluence-Url` HTTP headers and passes them directly to API client constructors without any SSRF validation.\n\n### Affected Package\n\n- **Ecosystem:** PyPI\n- **Package:** mcp-atlassian\n- **Affected versions:** all versions before fix commit 5cd697dfce91\n- **Patched versions:** \u003e= commit 5cd697dfce91\n\n### Details\n\nIn `main.py`, `_process_authentication_headers()` extracts URLs from ASGI headers without validation. In `dependencies.py`, `get_jira_fetcher()` creates `JiraConfig` with `url=jira_url_header` directly. There is no `validate_url` call, no IP range check, no hostname validation.\n\nThe fix adds URL validation to some paths but the header-based URL extraction in `_process_authentication_headers()` still passes raw URLs through. The derived config objects use the header URL directly and the fetcher makes HTTP requests to that URL.\n\n### PoC\n\n```python\njira_url_header = headers.get(b\"x-atlassian-jira-url\")\njira_url_str = jira_url_header.decode(\"latin-1\") if jira_url_header else None\nservice_headers[\"X-Atlassian-Jira-Url\"] = jira_url_str\n```\n\n**Steps to reproduce:**\n1. `git clone https://github.com/sooperset/mcp-atlassian /tmp/mcp-atlassian_test`\n2. `cd /tmp/mcp-atlassian_test \u0026\u0026 git checkout 5cd697dfce91~1`\n3. `pip install -e .`\n4. `python3 poc.py`\n\n**Expected output:**\n```\nVULNERABILITY CONFIRMED\nUser-supplied URLs from HTTP headers passed directly to JiraConfig/JiraFetcher with no SSRF validation\n```\n\n### Impact\n\nAn attacker can set `X-Atlassian-Jira-Url: http://169.254.169.254/latest/meta-data/` to access AWS instance metadata, or target any internal service. The server makes authenticated HTTP requests to the attacker-specified URL.\n\n### Suggested Remediation\n\nValidate all user-supplied URLs against an allowlist of permitted hostnames or reject private/loopback/link-local IP ranges. Consider requiring server-side configuration of allowed Atlassian instance URLs.","status":"published","published":"2026-10-01T16:38:36.0587Z","modified":"2026-10-01T17:45:10.027422041Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T15:52:57.255153Z"}]}}