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CVE-2026-63205— Zammad: Channel admins can read unauthorized attachments via signature rich-text body

Quick assessment

Affected
zammad zammad
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.

Zammad 是一款基于 Web 的开源帮助台/客户支持系统。在 7.1.2 版本之前，当创建或更新电子邮件签名时，Zammad 会处理签名正文中引用的内嵌图片。如果签名正文包含一个 HTML 标签，指向任何现有附件，系统会将该附件复制到一个由新签名拥有的记录中，而不会检查用户是否有权访问原始附件。新创建的副本随后可以由相同类型的 channel-admin 用户下载，因为附件访问权限是根据副本的所有者（即签名）而非原始对象（例如工单或知识库文章）来确定的。这使得拥有 admin.channel_email、adm

CVSS 5.1 · Medium EPSS 0.32% · P23

Possible ATT&CK Techniques 1 AI

T1005 · Data from Local System

Affected Version Matrix 1

VendorProduct Version RangeStatus
zammad zammad < 7.1.2 affected
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I. Basic Information for CVE-2026-63205

Vulnerability Information
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Vulnerability Title
Zammad: Channel admins can read unauthorized attachments via signature rich-text body
Source: CVE Program / CVE List V5
Vulnerability Description
Zammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, when creating or updating an email signature, Zammad processes inline images referenced in the signature body. If a signature body contains an HTML img tag pointing to any existing attachment, the system copies that attachment into a new signature-owned record, without checking whether the user has permission to access the original attachment. The newly created copy is then downloadable by the same channel-admin user, because attachment access is determined by the copy's owner (the signature), not the original object (e.g., a ticket or knowledge-base article). This allows a user with any of the admin.channel_email, admin.channel_google, admin.channel_microsoft365, or admin.channel_microsoft_graph permissions to read attachments they would otherwise be denied access to, such as ticket attachments belonging to groups they are not a member of. This issue is fixed in version 7.1.2.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
通过用户控制密钥绕过授权机制
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
zammad zammad < 7.1.2 -

II. Public POCs for CVE-2026-63205

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III. Intelligence Information for CVE-2026-63205

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Patches & Fixes for CVE-2026-63205 (1)

Same Patch Batch · zammad · 2026-09-25 · 30 CVEs total

CVE-2026-84458 9.1 CRITICAL Zammad: Account takeover via unverified email matching during SSO auto-link
CVE-2026-61525 8.8 HIGH Zammad: Arbitrary File Deletion via Unvalidated Session Identifier in Long Polling Control
CVE-2026-56733 8.7 HIGH Zammad: Incorrect Authorization and Improper Privilege Management
CVE-2026-56725 8.7 HIGH Zammad: Denial of Service via OTRS Import Controller
CVE-2026-84462 8.6 HIGH Zammad: AI Agent template sanitizer bypass leads to remote code execution
CVE-2026-56731 8.4 HIGH Zammad: Cross-Site Scripting in Ticket Notifications
CVE-2026-56724 7.1 HIGH Zammad: Incorrect implementation of permission checks in the knowledge base module
CVE-2026-56723 7.1 HIGH Zammad: Missing authorization on ticket attachment download
CVE-2026-56727 7.1 HIGH Zammad: PGP signature spoofing via unvalidated verification return
CVE-2026-84465 7.1 HIGH Zammad: S/MIME signature verification allows forged sender impersonation
CVE-2026-84464 7.1 HIGH Zammad: IDOR in External Data Source rendering exposes ticket, user, group, and organizati
CVE-2026-84461 6.9 MEDIUM Zammad: Missing rate limiting allows password brute-forcing during two-factor login
CVE-2026-63207 6.9 MEDIUM Zammad: Sensitive Information Exposure in Integration Administration API
CVE-2026-84463 6.3 MEDIUM Zammad: Stored HTML injection in Knowledge Base video widget enables forced session switch
CVE-2026-84460 5.3 MEDIUM Zammad: Missing Authorization in TagsController#list Allows Cross-Object Tag Enumeration
CVE-2026-56728 5.3 MEDIUM Zammad: Cross-User Taskbar Item Access Control Vulnerability
CVE-2026-56735 5.3 MEDIUM Zammad: Improper neutralization of `srcset` attribute in IMG tags in Zammad
CVE-2026-56732 5.3 MEDIUM Zammad: Malicious input in Ticket Body Enables Session Termination
CVE-2026-56734 5.3 MEDIUM Zammad: Avatar Image URL Server-Side Request Forwarding
CVE-2026-63206 5.3 MEDIUM Zammad: Remote image tracking bypass via shortened URL scheme

Showing top 20 of 30 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: zammad
Same vendor: zammad
Same weakness: CWE-639

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