CVE-2026-27826

high · 8.2

A public exploit / detection template exists

Weaponised detection is publicly available, which meaningfully raises real-world risk regardless of CVSS. nuclei-templates →

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to version 0.17.0, an unauthenticated attacker who can reach the mcp-atlassian HTTP endpoint can force the server process to make outbound HTTP requests to an arbitrary attacker-controlled URL by supplying two custom HTTP headers without an `Authorization` header. No authentication is required. The vulnerability exists in the HTTP middleware and dependency injection layer — not in any MCP tool handler - making it invisible to tool-level code analysis. In cloud deployments, this could enable theft of IAM role credentials via the instance metadata endpoint (`169[.]254[.]169[.]254`). In any HTTP deployment it enables internal network reconnaissance and injection of attacker-controlled content into LLM tool results. Version 0.17.0 fixes the issue.

8.2

CVSS

13.6%

EPSS (exploit prob.)

96th

EPSS percentile

2026-03-10

Published

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

Weaknesses

CWE-918

Affected products

Vendor	Product	Affected versions
sooperset	mcp_atlassian	< 0.17.0

Check a specific version with /api/v1/cve/match.

References

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-27826