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CVE-2026-77265— MCP Atlassian: SSRF via DNS Rebinding in Header-Based Authentication Flow

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 是面向 Atlassian 产品（Confluence 和 Jira）的 Model Context Protocol（MCP）服务器。在版本 0.22.0 之前，由 HTTP 请求头提供的 Jira 或 Confluence URL 在被 HTTP 客户端再次解析主机名以建立连接之前，会先被解析和验证。未认证的调用者可以利用 DNS 重绑定技术：在验证阶段，主机名返回一个公网 IP 地址；而在实际连接阶段，该主机名解析为一个内网 IP 地址。从而导致请求被发送到内部服务或元数据服务。

CVSS 5.9 · Medium EPSS 0.27% · P18

Affected Version Matrix 1

VendorProduct Version RangeStatus
sooperset mcp-atlassian < 0.22.0 affected
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I. Basic Information for CVE-2026-77265

Vulnerability Information
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Vulnerability Title
MCP Atlassian: SSRF via DNS Rebinding in Header-Based Authentication Flow
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, header-supplied Jira or Confluence URLs are resolved and validated before the HTTP client resolves the hostname again for the connection. An unauthenticated caller can use a DNS-rebinding hostname that returns a public address during validation and an internal address during connection, causing requests to internal or metadata services. The advisory traces the vulnerable input and processing flow through X-Atlassian-Jira-Url, X-Atlassian-Confluence-Url, validate_url_for_ssrf, and DNS rebinding, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
服务端请求伪造(SSRF)
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-2026-77265

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III. Intelligence Information for CVE-2026-77265

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Patches & Fixes for CVE-2026-77265 (1)

Vendor Pages for CVE-2026-77265 (1)

Other References for CVE-2026-77265 (1)

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-2026-77255 8.6 HIGH MCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue
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-2026-77247 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-2026-77257 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-2026-77271 8.3 HIGH MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (by
CVE-2026-77251 8.3 HIGH MCP Atlassian: JIRA_PROJECTS_FILTER / CONFLUENCE_SPACES_FILTER allow forbidden-project con
CVE-2026-77256 8.3 HIGH MCP Atlassian: OAuth refresh-token backup file is world-readable under default Unix umask
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 &rarr; →

IV. Related Vulnerabilities

Same product: mcp-atlassian
Same vendor: sooperset
Same weakness: CWE-918

V. Comments for CVE-2026-77265

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