[mcp-atlassian] Authentication bypass in HTTP transport: AtlassianOpaqueTokenVerifier accepts any non-empty token
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the HTTP transport accepts requests without a verified user identity and downstream fetcher construction falls back to the operator's globally configured Jira or Confluence credentials. A network client that can reach the MCP endpoint can invoke Atlassian tools as the operator, including read and write operations available to that account. The advisory traces the vulnerable input and processing flow through UserTokenMiddleware, AtlassianOpaqueTokenVerifier, _get_fetcher, and streamable-http, 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-2026-77244
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 11:01 UTC · Revision 1
Source evidence
[mcp-atlassian] Authentication bypass in HTTP transport: AtlassianOpaqueTokenVerifier accepts any non-empty token
core-osv · Original sourcePublished 22 Sept 2026, 17:49 UTC
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the HTTP transport accepts requests without a verified user identity and downstream fetcher construction falls back to the operator's globally configured Jira or Confluence credentials. A network client that can reach the MCP endpoint can invoke Atlassian tools as the operator, including read and write operations available to that account. The advisory traces the vulnerable input and processing flow through UserTokenMiddleware, AtlassianOpaqueTokenVerifier, _get_fetcher, and streamable-http, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
osv:CVE-2026-77244
Complete source record
{
"id": "ac8e314b431de9957649befb118fb2a2acc0a23febbfa05250bbdc9502e2992d",
"url": "https://osv.dev/vulnerability/CVE-2026-77244",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "[mcp-atlassian] Authentication bypass in HTTP transport: AtlassianOpaqueTokenVerifier accepts any non-empty token",
"summary": "MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the HTTP transport accepts requests without a verified user identity and downstream fetcher construction falls back to the operator's globally configured Jira or Confluence credentials. A network client that can reach the MCP endpoint can invoke Atlassian tools as the operator, including read and write operations available to that account. The advisory traces the vulnerable input and processing flow through UserTokenMiddleware, AtlassianOpaqueTokenVerifier, _get_fetcher, and streamable-http, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.",
"evidence": "osv:CVE-2026-77244",
"products": [],
"severity": "critical",
"structured": {
"id": "CVE-2026-77244",
"aliases": [
"CVE-2026-77244",
"GHSA-wrhw-j3f9-8vc6",
"PYSEC-2026-4103"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/sooperset/mcp-atlassian",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "b041733473f95119dd539542a43c280737a8e460"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "0.22.0"
}
],
"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": [
"v0.21.1",
"v0.21.0",
"v0.20.1",
"v0.20.0",
"v0.19.0",
"v0.18.1",
"v0.18.0",
"v0.17.0",
"v0.16.1",
"v0.16.0",
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"v0.10.3",
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"v0.10.1",
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"v0.9.0",
"v0.8.4",
"v0.8.3",
"v0.8.2",
"v0.8.1",
"v0.8.0",
"v0.7.1",
"v0.7.0",
"v0.6.5",
"v0.6.4",
"v0.6.3",
"v0.6.2",
"v0.6.1",
"v0.6.0",
"v0.5.0",
"v0.4.0",
"v0.3.1",
"v0.3.0",
"v0.2.6",
"v0.2.5",
"v0.2.4",
"v0.2.3",
"v0.2.2",
"v0.2.1",
"v0.2.0",
"v0.1.16",
"v0.1.15",
"v0.1.14",
"v0.1.13",
"v0.1.12",
"v0.1.11",
"v0.1.10",
"v0.1.8",
"v0.1.7",
"v0.1.6",
"v0.1.5",
"v0.1.4"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-77244.json"
}
}
],
"modified": "2026-10-28T02:30:28.293107727Z",
"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-2026-77244.json",
"https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-wrhw-j3f9-8vc6",
"https://nvd.nist.gov/vuln/detail/CVE-2026-77244",
"https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460",
"https://github.com/sooperset/mcp-atlassian/pull/1448"
],
"provider_metadata": {
"cwe_ids": [
"CWE-287",
"CWE-303",
"CWE-862"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77244.json"
}
},
"related_cves": [
{
"value": "CVE-2026-77244",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 494813,
"published_at": "2026-09-22T17:49:38.296+00:00"
}