CVE-2026-77243 json
MCP Atlassian: ENABLED_TOOLS / Toolset authorization bypass
published 2026-09-22 47 d ago modified 2026-10-01 38 d ago also GHSA-3r68-hf9h-887v , PYSEC-2026-4081 , EUVD-2026-84626
- cvss
- 8.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 45%
- public exploits
- 0
- none known
Summary
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, ENABLED_TOOLS and TOOLSETS are applied when tools are listed but are not rechecked when a tools/call request is dispatched. A client that knows a hidden tool name can directly invoke excluded read, write, or delete tools despite the operator's configured least-privilege restrictions. The advisory traces the vulnerable input and processing flow through ENABLED_TOOLS, TOOLSETS, tools/list, tools/call, and _call_tool_mcp, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
Patch / fix
- pypi mcp-atlassian 0.22.0
- mcp-atlassian mcp_atlassian 0.22.0
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 47 d ago
Exploit prediction
0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-3r68-hf9h-887v referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| OSV | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | mcp-atlassian | <0.22.0 |
0.22.0 |
Affected products
- sooperset mcp-atlassian
Classification
- Weakness
-
- CWE-862 Missing Authorization
References
-
github.com
/sooperset/mcp-atlassian/pull/1448
web, issue-tracking, patch
-
github.com
/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460
web, patch
-
github.com
/sooperset/mcp-atlassian/security/advisories/GHSA-3r68-hf9h-887v
exploit, web, vendor-advisory
-
github.com
/sooperset/mcp-atlassian/releases/tag/v0.22.0
web, release-notes
-
nvd.nist.gov
/vuln/detail/CVE-2026-77243
advisory
-
github.com
/sooperset/mcp-atlassian
package
-
pypi.org
/project/mcp-atlassian
package
-
github.com
/advisories/GHSA-3r68-hf9h-887v
advisory
Sources
- CVE List CVE-2026-77243
- GitHub Advisory GHSA-3r68-hf9h-887v
- NVD CVE-2026-77243
- OSV PYSEC-2026-4081
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.