---
id: CVE-2026-77274
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, validate_url_for_ssrf has a backslash
  authority confusion because it interprets the authority differently from the
  Requ…
severity: high
cvss: 8.8
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/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-2026-77274'
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-hgcf-4mq8-5266
    label: security-advisories@github.com
  - url: >-
      https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-hgcf-4mq8-5266
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77274'
  - url: 'https://github.com/advisories/GHSA-hgcf-4mq8-5266'
  - url: 'https://github.com/sooperset/mcp-atlassian'
tags:
  - nvd
  - cve.org
  - exploit-available
  - ghsa
  - pip
  - osv
epss: 0.00665
epssPercentile: 0.5037
aliases:
  - GHSA-hgcf-4mq8-5266
ecosystem: pip
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-22T18:31:53.866509Z'
cvssSource: cna
ingestedAt: '2026-09-22T18:08:12.497Z'
---

## Overview

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, validate_url_for_ssrf has a backslash authority confusion because it interprets the authority differently from the Requests connection layer in the header-based Jira and Confluence URL authentication flow. A crafted URL can validate as an external hostname while the HTTP client connects to an internal host, permitting server-side requests to protected network resources. 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-2026-77274)

Affected packages:

- `mcp-atlassian < 0.22.0`

Patched in:

- `mcp-atlassian 0.22.0`

Source: https://github.com/advisories/GHSA-hgcf-4mq8-5266