CVE-2026-77250
Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, OAuthConfig writes a plaintext fallback file containing access and refresh tokens under the user's .mcp-atlassian directory using process-default permissions. On systems with a permissive umask, same-group or other local users and processes can read the persisted tokens and reuse the associated Atlassian access. The advisory traces the vulnerable input and processing flow through OAuthConfig._save_tokens, ~/.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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
mcp-atlassianPyPI | < 0.22.0 | 0.22.0 |
Affected products
3cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:*range: <0.22.0
- (no CPE)range: <0.22.0
- Range: <0.22.0
Patches
Vulnerability mechanics
References
6- github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460nvdPatchWEB
- github.com/sooperset/mcp-atlassian/pull/1448nvdIssue TrackingPatchWEB
- github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6nvdExploitVendor AdvisoryWEB
- github.com/advisories/GHSA-g5xv-mhgm-v5f6ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-77250ghsaADVISORY
- github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0nvdRelease NotesWEB
News mentions
1- Atlassian MCP: 25 Coordinated Vulnerabilities Expose Jira, Confluence IntegrationsVypr Intelligence · Sep 22, 2026