CVE-2026-77256 (GCVE-0-2026-77256)
Vulnerability from cvelistv5
Published
2026-09-22 18:48
Modified
2026-09-22 19:08
Severity ?
8.3 (High) - CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
CWE
  • CWE-732 - Incorrect Permission Assignment for Critical Resource
Summary
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the plaintext OAuth fallback file containing refresh and access tokens is written with permissions inherited from the process umask. Under common or permissive configurations, other local users can read the backup and retain Atlassian access through the refresh token. The advisory traces the vulnerable input and processing flow through OAuthConfig._save_tokens_to_file, refresh_token, access_token, and umask, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
References
Impacted products
Vendor Product Version
sooperset mcp-atlassian Version: < 0.22.0
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