Medium 5.5Published Sep 22, 2026

CVE-2026-77268MCP Atlassian: Insecure File Permissions on OAuth Token Storage

Updated under an hour ago (2026-10-19 07:23 UTC)

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It affects sooperset mcp-atlassian and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for sooperset mcp-atlassian

Exploited in the last 30 days

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.

CVSS: 5.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Weakness (CWE): CWE-732
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Sep 23, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

sooperset mcp-atlassian sooperset:mcp_atlassian (from the name)	before 0.22.0	CNA record
mcp-atlassian mcp_atlassian mcp-atlassian:mcp_atlassian	before 0.22.0	NVD

References

https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-4596-2p6p-28cvx-refsource-confirm, exploit, mitigation, vendor-advisory
https://github.com/sooperset/mcp-atlassian/pull/1448x-refsource-misc, issue-tracking, patch
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460x-refsource-misc, patch
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.