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CVE-2026-77255— MCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue

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，Jira 的 API 中 参数会被直接转换为本地文件路径，并绕过工作区验证，直接路由至附件上传实现。攻击者可利用此缺陷，通过将该 MCP 服务器作为“混淆副手”（confused deputy），读取任意本地文件并将其作为附件附加到 Jira 工单中，从而窃取文件内容。 安全公告详细追踪了该漏洞在 、 、 和 等环节中的脆弱输

CVSS 8.6 · High EPSS 0.46% · P40

Affected Version Matrix 1

VendorProduct Version RangeStatus
sooperset mcp-atlassian < 0.22.0 affected
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I. Basic Information for CVE-2026-77255

Vulnerability Information
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Vulnerability Title
MCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue
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 Jira update_issue attachments argument is converted into local paths and routed to the attachment upload implementation without workspace validation. A caller can make the MCP server read arbitrary local files and attach them to a Jira issue, using the server as a confused deputy to exfiltrate the contents. The advisory traces the vulnerable input and processing flow through jira update_issue, attachments, upload_attachment, and file_path, 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:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
对路径名的限制不恰当(路径遍历)
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-2026-77255

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III. Intelligence Information for CVE-2026-77255

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Patches & Fixes for CVE-2026-77255 (1)

Vendor Pages for CVE-2026-77255 (1)

Other References for CVE-2026-77255 (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-2026-77262 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-2026-77271 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
CVE-2026-77270 6.5 MEDIUM MCP Atlassian: Arbitrary File Read via Upload Attachment Tools

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-22