MCP Atlassian: Unauthenticated arbitrary local file read via upload_attachment file_path, chained with missing auth on streamable-http transport
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the streamable HTTP transport accepts requests without a user identity and falls back to operator credentials, while upload_attachment accepts an unrestricted file_path. An unauthenticated network caller can read files available to the MCP process, upload them to an attacker-selected Jira issue or Confluence page, and retrieve the contents. The advisory traces the vulnerable input and processing flow through streamable-http, UserTokenMiddleware, upload_attachment, file_path, and _get_fetcher, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-77248
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 2 Nov 2026, 15:31 UTC · Revision 1
Source evidence
MCP Atlassian: Unauthenticated arbitrary local file read via upload_attachment file_path, chained with missing auth on streamable-http transport
core-osv · Original sourcePublished 22 Sept 2026, 18:49 UTC
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the streamable HTTP transport accepts requests without a user identity and falls back to operator credentials, while upload_attachment accepts an unrestricted file_path. An unauthenticated network caller can read files available to the MCP process, upload them to an attacker-selected Jira issue or Confluence page, and retrieve the contents. The advisory traces the vulnerable input and processing flow through streamable-http, UserTokenMiddleware, upload_attachment, file_path, and _get_fetcher, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
osv:CVE-2026-77248
Complete source record
{
"id": "ec2b9a41f7802cb239ab05a662bb8766ba49f9a83cb0bc107c4d3feefb9a4922",
"url": "https://osv.dev/vulnerability/CVE-2026-77248",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "MCP Atlassian: Unauthenticated arbitrary local file read via upload_attachment file_path, chained with missing auth on streamable-http transport",
"summary": "MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the streamable HTTP transport accepts requests without a user identity and falls back to operator credentials, while upload_attachment accepts an unrestricted file_path. An unauthenticated network caller can read files available to the MCP process, upload them to an attacker-selected Jira issue or Confluence page, and retrieve the contents. The advisory traces the vulnerable input and processing flow through streamable-http, UserTokenMiddleware, upload_attachment, file_path, and _get_fetcher, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.",
"evidence": "osv:CVE-2026-77248",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2026-77248",
"aliases": [
"CVE-2026-77248",
"GHSA-cc5h-2pwp-pvcc",
"PYSEC-2026-4089"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/sooperset/mcp-atlassian",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "b041733473f95119dd539542a43c280737a8e460"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
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"introduced": "0"
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{
"fixed": "0.22.0"
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"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "b041733473f95119dd539542a43c280737a8e460"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "b041733473f95119dd539542a43c280737a8e460"
}
],
"source": "REFERENCES_TAG",
"original_tag": "v0.22.0"
},
{
"cpe": "cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "0.22.0"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
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"v0.21.0",
"v0.20.1",
"v0.20.0",
"v0.19.0",
"v0.18.1",
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"v0.7.0",
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"v0.6.0",
"v0.5.0",
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"v0.3.0",
"v0.2.6",
"v0.2.5",
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"v0.2.0",
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"v0.1.8",
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-77248.json"
}
}
],
"modified": "2026-10-28T02:30:20.676795389Z",
"provider": "osv",
"references": [
"https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77248.json",
"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-cc5h-2pwp-pvcc",
"https://nvd.nist.gov/vuln/detail/CVE-2026-77248",
"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460",
"https://github.com/sooperset/mcp-atlassian/pull/1448"
],
"provider_metadata": {
"cwe_ids": [
"CWE-22",
"CWE-306"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77248.json"
}
},
"related_cves": [
{
"value": "CVE-2026-77248",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 486560,
"published_at": "2026-09-22T18:49:57.295+00:00"
}