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CVE-2026-27826

Sooperset Mcp Atlassian server-side request forgery (SSRF)

8.2 HIGHPublic exploitEPSS 1.04%
  1. Published10 Mar 2026

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.

CVSS 3.1 breakdown

Attack vectorAdjacent
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeChanged
ConfidentialityHigh
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

Affected products

Sooperset Mcp Atlassian< 0.17.0

Remediation

Fixed in
Sooperset Mcp Atlassian≥ 0.17.0

References

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Frequently asked

Is CVE-2026-27826 being actively exploited?

CVE-2026-27826 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 1.04%.

How severe is CVE-2026-27826?

CVE-2026-27826 has a CVSS 3.1 base score of 8.2, rated high. EPSS estimates a 1.04% probability of exploitation.

Which products are affected by CVE-2026-27826?

Affected products include Sooperset Mcp Atlassian.

How do I fix CVE-2026-27826?

Upgrade affected software to a fixed version, for example Sooperset Mcp Atlassian 0.17.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.