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Vulnerabilities

Vulnerability · CVE-2026-27826

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira).

Published Mar 10, 2026 · catalog updated Jun 17, 2026 · mcp atlassian

Check if you run it

No confirmed exploitation is on record for CVE-2026-27826. EPSS is 1.04%. Act only if a listed version of mcp atlassian is installed.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.2
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.04%
Remediation
Advisory link
Affected products
cpe sooperset/mcp atlassian

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 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 ( ). 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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe sooperset/mcp atlassianversion unspecified

How to fix CVE-2026-27826

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-27826. EPSS is 1.04%. Act only if a listed version of mcp atlassian is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-918: Server-Side Request Forgery (SSRF). EPSS 1.04%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 10, 2026 · NIST NVD

    Detected

    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 header. No authentication is required. The vulnerabi

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 header. No authentication is required. The vulnerabi

Sources

  • CVE.orgVulnerability recordCVE-2026-27826

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-27826

    30-day exploitation probability 1.0%

    first.org
  • NIST NVDVulnerability recordCVE-2026-27826

    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 atta

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.