CVE-2026-77268— MCP Atlassian: Insecure File Permissions on OAuth Token Storage
Quick assessment
Affected
sooperset mcp-atlassian
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the OAuth fallback token directory and JSON file are created without explicit owner-only modes. Local users or processes with access through t
Affected Version Matrix 1
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| sooperset | mcp-atlassian | < 0.22.0 |
affected |
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I. Basic Information for CVE-2026-77268
Vulnerability Information
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Vulnerability Title
MCP Atlassian: Insecure File Permissions on OAuth Token Storage
Source: CVE Program / CVE List V5
Vulnerability Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the OAuth fallback token directory and JSON file are created without explicit owner-only modes. Local users or processes with access through the resulting group or world permission bits can read access and refresh tokens and reuse the associated Atlassian session. The advisory traces the vulnerable input and processing flow through ~/.mcp-atlassian, oauth-<client_id>.json, access_token, and refresh_token, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
关键资源的不正确权限授予
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| sooperset | mcp-atlassian | < 0.22.0 | - |
|
II. Public POCs for CVE-2026-77268
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-77268 (1)
Vendor Pages for CVE-2026-77268 (1)
Other References for CVE-2026-77268 (1)
Same Patch Batch · sooperset · 2026-09-22 · 29 CVEs total
| CVE-2026-77244 | 10.0 CRITICAL | [mcp-atlassian] Authentication bypass in HTTP transport: AtlassianOpaqueTokenVerifier acce |
| CVE-2026-77254 | 9.1 CRITICAL | MCP Atlassian: Unauthenticated HTTP MCP requests can use globally configured Jira and Conf |
| CVE-2026-77274 | 8.8 HIGH | MCP Atlassian: SSRF Protection Bypass |
| CVE-2026-77243 | 8.8 HIGH | MCP Atlassian: ENABLED_TOOLS / Toolset authorization bypass |
| CVE-2026-77255 | 8.6 HIGH | MCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue |
| CVE-2026-77262 | 8.6 HIGH | MCP Atlassian: Path Traversal / Arbitrary File Read in confluence_upload_attachment MCP to |
| CVE-2026-77248 | 8.6 HIGH | MCP Atlassian: Unauthenticated arbitrary local file read via upload_attachment file_path, |
| CVE-2026-77247 | 8.3 HIGH | MCP Atlassian: Arbitrary server-local file upload to Jira/Confluence attachments via unres |
| CVE-2026-77260 | 8.3 HIGH | MCP Atlassian: Arbitrary local file READ via unconstrained file_path in upload_attachment |
| CVE-2026-77257 | 8.3 HIGH | MCP Atlassian: HTTP upload tools accept arbitrary server-local file paths |
| CVE-2026-77267 | 8.3 HIGH | mcp-atlassian has an incomplete SSRF remediation |
| CVE-2026-77251 | 8.3 HIGH | MCP Atlassian: JIRA_PROJECTS_FILTER / CONFLUENCE_SPACES_FILTER allow forbidden-project con |
| CVE-2026-77271 | 8.3 HIGH | MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (by |
| CVE-2026-77256 | 8.3 HIGH | MCP Atlassian: OAuth refresh-token backup file is world-readable under default Unix umask |
| CVE-2026-77259 | 7.7 HIGH | MCP Atlassian: Arbitrary file read via confluence_upload_attachment allows exfiltration of |
| CVE-2026-77258 | 7.7 HIGH | MCP Atlassian: Arbitrary file read/exfiltration via upload_attachment missing validate_saf |
| CVE-2026-77242 | 7.5 HIGH | MCP Atlassian: Incomplete fix for CVE-2026-27826: DNS rebinding bypasses SSRF validation ( |
| CVE-2026-77246 | 7.4 HIGH | MCP Atlassian: MCP HTTP Client Server-Local File Exfiltration via Unvalidated Attachment U |
| CVE-2026-77253 | 7.1 HIGH | MCP Atlassian: Jira and Confluence attachment upload tools can read arbitrary server-local |
| CVE-2026-77261 | 7.1 HIGH | MCP Atlassian: SSRF redirect protection missing for basic-auth and OAuth authentication br |
Showing top 20 of 29 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same product: mcp-atlassian
-
CVE-2026-77246
MCP Atlassian: MCP HTTP Client Server-Local File Exfiltratio -
CVE-2026-77248
MCP Atlassian: Unauthenticated arbitrary local file read via -
CVE-2026-77256
MCP Atlassian: OAuth refresh-token backup file is world-read -
CVE-2026-77249
MCP Atlassian: Incomplete fix for CVE-2026-27826: redirect-b -
CVE-2026-77259
MCP Atlassian: Arbitrary file read via confluence_upload_att
Same vendor: sooperset
-
CVE-2026-77246
MCP Atlassian: MCP HTTP Client Server-Local File Exfiltratio -
CVE-2026-77248
MCP Atlassian: Unauthenticated arbitrary local file read via -
CVE-2026-77256
MCP Atlassian: OAuth refresh-token backup file is world-read -
CVE-2026-77249
MCP Atlassian: Incomplete fix for CVE-2026-27826: redirect-b -
CVE-2026-77259
MCP Atlassian: Arbitrary file read via confluence_upload_att
Same weakness: CWE-732
V. Comments for CVE-2026-77268
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