---
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: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-918
vendor: mcp-atlassian
product: mcp_atlassian
affected:
  - mcp_atlassian < 0.22.0
patched:
  - mcp_atlassian 0.22.0
published: '2026-09-22'
updated: '2026-09-29'
sourceUpdated: '2026-09-29T18:59:56.113'
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://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-5wf4-jqxh-8gm3
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - 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'
  - url: 'https://pypi.org/project/mcp-atlassian'
tags:
  - nvd
  - cve.org
  - exploit-available
  - ghsa
  - pip
  - osv
epss: 0.0032
epssPercentile: 0.24881
aliases:
  - GHSA-5wf4-jqxh-8gm3
  - PYSEC-2026-4084
ecosystem: pip
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-28T17:18:42.777642Z'
scores:
  nvd: 6.5
  cna: 8.3
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.

## Affected

- `mcp_atlassian < 0.22.0`

## Remediation

Upgrade past the affected range:

- `mcp_atlassian 0.22.0`

## 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