---
id: CVE-2026-77272
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 OAuth error query parameter is
  passed to CallbackHandler._send_response in oauth_setup.py and interpolated
  into an …
severity: medium
cvss: 5.4
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N'
cwe:
  - CWE-79
vendor: mcp-atlassian
product: mcp_atlassian
affected:
  - mcp_atlassian < 0.22.0
patched:
  - mcp_atlassian 0.22.0
published: '2026-09-22'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T13:10:43.460'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77272'
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-g2r2-3j32-j27x
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-g2r2-3j32-j27x'
  - url: 'https://github.com/sooperset/mcp-atlassian'
  - url: 'https://pypi.org/project/mcp-atlassian'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-77272'
tags:
  - nvd
  - cve.org
  - ghsa
  - pip
  - osv
epss: 0.00262
epssPercentile: 0.17924
aliases:
  - GHSA-g2r2-3j32-j27x
  - PYSEC-2026-4093
ecosystem: pip
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-23T14:10:19.747917Z'
ingestedAt: '2026-09-22T19:09:10.008Z'
---

## Overview

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the OAuth error query parameter is passed to CallbackHandler._send_response in oauth_setup.py and interpolated into an HTML page without escaping. A crafted authorization callback can inject markup or script that executes in the browser of a user completing the OAuth flow. 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-2026-77272)

Affected packages:

- `mcp-atlassian < 0.22.0`

Patched in:

- `mcp-atlassian 0.22.0`

Source: https://github.com/advisories/GHSA-g2r2-3j32-j27x