PatchTheCVECVE-2026-77266: MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira)
CVE-2026-77266 is a medium-severity flaw (CVSS 6.5) affecting mcp atlassian. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, upload_attachment accepts absolute paths and traversal sequences without constraining the resolved path to the server workspace. An MCP caller with attachment access can read a chosen server-local file and exfiltrate it through Jira or Confluence. The advisory traces the vulnerable input and processing flow through upload_attachme
Why this priority
- Public exploit reference
A fixed release or distro patch exists.
Risk facts
| CVSS score | 6.5 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 0.5% (top 57%) |
| CISA exploited list | No |
| Weakness | CWE-22 |
| Published | 2026-09-22 |
| Last modified | 2026-09-28 |
Last updated 2026-09-28 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-77266?
mcp atlassian: upgrade to 0.22.0. Exact commands for each OS are on this page.
Is CVE-2026-77266 being exploited?
CVE-2026-77266 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-77266 affect?
CVE-2026-77266 affects mcp atlassian. Severity is medium (CVSS 6.5). MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, upload_attachment accepts absolute paths and traversal sequences without constraining the resolved path to the server work
How urgent is CVE-2026-77266?
Priority 38/100. Public exploit reference
Software pages
Atlassian Confluence vulnerabilities · Atlassian Jira vulnerabilities
Related CVEs
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- CVE-2026-77262 HIGH 8.6 UPGRADE MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira)