mcp-atlassian incomplete SSRF remediation (CVE-2026-77267)

The mcp-atlassian package fails to validate URLs extracted from HTTP headers before passing them to API clients, allowing attackers to perform Server-Side Request Forgery attacks against internal services and cloud metadata endpoints.

Disclosed 22 September 2026 · Record updated 1 October 2026

Impact

Attackers can make authenticated HTTP requests to arbitrary URLs including internal services and cloud metadata endpoints by supplying malicious URLs in HTTP headers.

Our coverage

A factory worker passes unmarked packages directly from the loading dock through security gates into restricted rooms, bypassing inspection checkpoints.

Vulnerabilities

Atlassian MCP server still open to SSRF after partial fix

A GitHub advisory published on 22 September 2026 says mcp-atlassian passes URLs from HTTP headers straight to its API clients without checks.

22 Sept 2026

Sources

github.comhttps://github.com/advisories/GHSA-5wf4-jqxh-8gm3