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CVE-2026-77251highCWE-1276

MCP Atlassian: JIRA_PROJECTS_FILTER / CONFLUENCE_SPACES_FILTER allow forbidden-project content exfiltration (one LIVE-proven on Atlassian Cloud)

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 8.3epss 0.2%
exploitation probability
0.2%top 86% of all CVEs
observed exploitation
nono source reports it
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, Jira search accepts a forbidden project clause because it checks only for the presence of project syntax, Confluence search uses an incomplete case-sensitive space check, and Jira board APIs omit project-filter enforcement. These paths expose issues, boards, or pages outside JIRA_PROJECTS_FILTER or CONFLUENCE_SPACES_FILTER when the operator credentials have broader access. The advisory traces the vulnerable input and processing flow through jira_search, confluence_search, get_board_issues, get_agile_boards, JIRA_PROJECTS_FILTER, and CONFLUENCE_SPACES_FILTER, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
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