CVE-2026-77244

CRITICAL 10.0

[mcp-atlassian] Authentication bypass in HTTP transport: AtlassianOpaqueTokenVerifier accepts any non-empty token

CVSS Score

10.0

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-287 CWE-303 CWE-862
Vendor	sooperset
Product	mcp-atlassian
Published	Sep 22, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Affected Versions

sooperset / mcp-atlassian

< 0.22.0

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-wrhw-j3f9-8vc6 github.com: https://github.com/sooperset/mcp-atlassian/pull/1448 github.com: https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 github.com: https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0