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CVE-2026-77266— MCP Atlassian: Path traversal in upload_attachment allows arbitrary file read and exfiltration via MCP tool call

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 是一个面向 Atlassian 产品（Confluence 和 Jira）的模型上下文协议（MCP）服务器。在版本 0.22.0 之前，函数接受绝对路径和路径遍历序列，而未将解析后的路径限制在服务器工作区内。拥有附件访问权限的 MCP 调用者可以读取指定的服务器本地文件，并通过 Jira 或 Confluence 将其外泄。该安全公告追踪了、以及路径遍历相关的漏洞输入和处理流程，从而识别出受影响的入口点、控制逻辑和代码路径。此问题已在版本 0.22.0 中修复。

CVSS 6.5 · Medium EPSS 0.44% · P37 Updated Sep 23, 2026

Possible ATT&CK Techniques 2 AI

T1567 · Exfiltration Over Web Service T1082 · System Information Discovery

Affected Version Matrix 1

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

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Vulnerability Information

Have questions about the vulnerability? See if Shenlong's analysis helps!

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Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title

MCP Atlassian: Path traversal in upload_attachment allows arbitrary file read and exfiltration via MCP tool call

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, upload_attachment accepts absolute paths and traversal sequences without constraining the resolved path to the server workspace. An MCP caller with attachment access can read a chosen server-local file and exfiltrate it through Jira or Confluence. The advisory traces the vulnerable input and processing flow through upload_attachment, file_path, and path traversal, 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:L/UI:N/S:U/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-2026-77266

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-77266

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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-2026-77255	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-2026-77251	8.3 HIGH	MCP Atlassian: JIRA_PROJECTS_FILTER / CONFLUENCE_SPACES_FILTER allow forbidden-project con
CVE-2026-77271	8.3 HIGH	MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (by
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 → →

IV. Related Vulnerabilities

Same product: mcp-atlassian

Same vendor: sooperset

Same weakness: CWE-22

V. Comments for CVE-2026-77266

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Goal Reached Thanks to every supporter — we hit 100%!

CVE-2026-77266— MCP Atlassian: Path traversal in upload_attachment allows arbitrary file read and exfiltration via MCP tool call

Quick assessment

Possible ATT&CK Techniques 2 AI

Affected Version Matrix 1

I. Basic Information for CVE-2026-77266

Vulnerability Information

Vulnerability Title

Vulnerability Description

CVSS Information

Vulnerability Type

Affected Products

II. Public POCs for CVE-2026-77266

III. Intelligence Information for CVE-2026-77266

Patches & Fixes for CVE-2026-77266 (1)

Vendor Pages for CVE-2026-77266 (1)

Other References for CVE-2026-77266 (1)

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

IV. Related Vulnerabilities

V. Comments for CVE-2026-77266

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