---
id: CVE-2026-77267
title: >-
  MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products
  (Confluence and Jira)
summary: >-
  MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products
  (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and
  X-Atlassian-Confluence-Url headers are processed by
  _process_authentication_headers and us…
severity: high
cvss: 8.3
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N'
cwe:
  - CWE-918
vendor: sooperset
product: mcp-atlassian
affected:
  - mcp-atlassian < 0.22.0
patched:
  - mcp-atlassian 0.22.0
published: '2026-09-22'
updated: '2026-09-23'
sourceUpdated: '2026-09-23T18:28:25.093'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77267'
references:
  - url: >-
      https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460
    label: security-advisories@github.com
  - url: 'https://github.com/sooperset/mcp-atlassian/pull/1448'
    label: security-advisories@github.com
  - url: 'https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0'
    label: security-advisories@github.com
  - url: >-
      https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-5wf4-jqxh-8gm3
    label: security-advisories@github.com
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77267'
  - url: 'https://github.com/advisories/GHSA-5wf4-jqxh-8gm3'
  - url: 'https://github.com/sooperset/mcp-atlassian'
tags:
  - nvd
  - cve.org
  - ghsa
  - pip
  - osv
epss: 0.00335
epssPercentile: 0.24078
aliases:
  - GHSA-5wf4-jqxh-8gm3
ecosystem: pip
cvssSource: cna
ingestedAt: '2026-09-22T18:08:12.472Z'
---

## Overview

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination, bypassing the incomplete CVE-2026-27826 remediation. This issue is fixed in version 0.22.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-77267)

Affected packages:

- `mcp-atlassian < 0.22.0`

Patched in:

- `mcp-atlassian 0.22.0`

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