CVEvulnerability

CVE-2026-77256

8.3 HIGH Published 2026-09-22 Modified 2026-09-28 Official page ↗
Status
Analyzed
Published
2026-09-22
Last modified
2026-09-28
Assigner
[email protected]
CVSS 4.0 ([email protected])
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
6.5 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Weaknesses
CWE-732

Description

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.

Affected configurations

• mcp-atlassian mcp atlassian (< 0.22.0)

Related

Weakness · CWE (1)

  • CWE-732 Incorrect Permission Assignment for Critical Resource weakness

References