AUGUST 4, 2026
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Case File

CVE-2026-27826

HIGH · CVSS 8.2 EPSS 13.63% Public Exploit

Source: NVD + CISA KEV + EPSS (historical backfill) · Published 2026-03-10 · Last synced 2026-08-04

CyberRota Analysis

This is a high severity vulnerability with a CVSS score of 8.2. Public exploit code or proof-of-concept references have been detected in its references. Its EPSS score suggests a 13.6% probability of exploitation in the next 30 days. Exploitation may require the attacker to be authenticated.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-27826
Severity
HIGH
CVSS
8.2
EPSS
13.63%

Original NVD Description

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.