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CVE-2026-77272— MCP Atlassian: Reflected XSS in OAuth Setup Callback Handler

Quick assessment

Affected

sooperset mcp-atlassian

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

MCP Atlassian 是一款面向 Atlassian 产品（Confluence 和 Jira）的 Model Context Protocol（MCP）服务器。在 0.22.0 版本之前，OAuth 错误查询参数会被传递到中的方法，并未经转义直接插入到 HTML 页面中。攻击者可以利用构造好的授权回调，在用户完成 OAuth 流程时，在其浏览器中注入并执行恶意标记或脚本。该问题已在 0.22.0 版本中得到修复。

CVSS 5.4 · Medium EPSS 0.25% · P15 Updated Sep 23, 2026

Possible ATT&CK Techniques 1 AI

T1059.007 · JavaScript

Affected Version Matrix 1

Vendor	Product	Version Range	Status
sooperset	mcp-atlassian	`< 0.22.0`	affected

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Vulnerability Information

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Vulnerability Title

MCP Atlassian: Reflected XSS in OAuth Setup Callback Handler

Source: CVE Program / CVE List V5

Vulnerability Description

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.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Source: CVE Program / CVE List V5

Vulnerability Type

在Web页面生成时对输入的转义处理不恰当(跨站脚本)

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
sooperset	mcp-atlassian	< 0.22.0	-

II. Public POCs for CVE-2026-77272

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-77272

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Same Patch Batch · sooperset · 2026-09-22 · 29 CVEs total

CVE-2026-77244	10.0 CRITICAL	[mcp-atlassian] Authentication bypass in HTTP transport: AtlassianOpaqueTokenVerifier acce
CVE-2026-77254	9.1 CRITICAL	MCP Atlassian: Unauthenticated HTTP MCP requests can use globally configured Jira and Conf
CVE-2026-77274	8.8 HIGH	MCP Atlassian: SSRF Protection Bypass
CVE-2026-77243	8.8 HIGH	MCP Atlassian: ENABLED_TOOLS / Toolset authorization bypass
CVE-2026-77262	8.6 HIGH	MCP Atlassian: Path Traversal / Arbitrary File Read in confluence_upload_attachment MCP to
CVE-2026-77248	8.6 HIGH	MCP Atlassian: Unauthenticated arbitrary local file read via upload_attachment file_path,
CVE-2026-77255	8.6 HIGH	MCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue
CVE-2026-77271	8.3 HIGH	MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (by
CVE-2026-77247	8.3 HIGH	MCP Atlassian: Arbitrary server-local file upload to Jira/Confluence attachments via unres
CVE-2026-77260	8.3 HIGH	MCP Atlassian: Arbitrary local file READ via unconstrained file_path in upload_attachment
CVE-2026-77256	8.3 HIGH	MCP Atlassian: OAuth refresh-token backup file is world-readable under default Unix umask
CVE-2026-77257	8.3 HIGH	MCP Atlassian: HTTP upload tools accept arbitrary server-local file paths
CVE-2026-77267	8.3 HIGH	mcp-atlassian has an incomplete SSRF remediation
CVE-2026-77251	8.3 HIGH	MCP Atlassian: JIRA_PROJECTS_FILTER / CONFLUENCE_SPACES_FILTER allow forbidden-project con
CVE-2026-77259	7.7 HIGH	MCP Atlassian: Arbitrary file read via confluence_upload_attachment allows exfiltration of
CVE-2026-77258	7.7 HIGH	MCP Atlassian: Arbitrary file read/exfiltration via upload_attachment missing validate_saf
CVE-2026-77242	7.5 HIGH	MCP Atlassian: Incomplete fix for CVE-2026-27826: DNS rebinding bypasses SSRF validation (
CVE-2026-77246	7.4 HIGH	MCP Atlassian: MCP HTTP Client Server-Local File Exfiltration via Unvalidated Attachment U
CVE-2026-77253	7.1 HIGH	MCP Atlassian: Jira and Confluence attachment upload tools can read arbitrary server-local
CVE-2026-77261	7.1 HIGH	MCP Atlassian: SSRF redirect protection missing for basic-auth and OAuth authentication br

Showing top 20 of 29 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: mcp-atlassian

Same vendor: sooperset

Same weakness: CWE-79

V. Comments for CVE-2026-77272

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CVE-2026-77272— MCP Atlassian: Reflected XSS in OAuth Setup Callback Handler

Quick assessment

Possible ATT&CK Techniques 1 AI

Affected Version Matrix 1

I. Basic Information for CVE-2026-77272

Vulnerability Information

Vulnerability Title

Vulnerability Description

CVSS Information

Vulnerability Type

Affected Products

II. Public POCs for CVE-2026-77272

III. Intelligence Information for CVE-2026-77272

Patches & Fixes for CVE-2026-77272 (1)

Vendor Pages for CVE-2026-77272 (1)

Other References for CVE-2026-77272 (1)

Same Patch Batch · sooperset · 2026-09-22 · 29 CVEs total

IV. Related Vulnerabilities

V. Comments for CVE-2026-77272

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