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CVE-2026-56727— Zammad: PGP signature spoofing via unvalidated verification return

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 Zammad 7.0.2 版本之前，在处理传入的 PGP 邮件时，GnuPG（gpg）验证调用的返回值被静默丢弃。无论 gpg 返回的结果是有效签名、无效签名还是缺失签名，处理程序都会无条件地将 写入文章的安全偏好设置中。 影响：任何发送方都可以篡改 multipart/signed 格式 PGP 邮件的主体内容，或构造带有完全伪造或不匹配签名的消息，而 Zammad 仍会向收件人显示该消息已通过加密验证，并标注为“Good signature”（签

CVSS 7.1 · High EPSS 0.25% · P14
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I. Basic Information for CVE-2026-56727

Vulnerability Information
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Vulnerability Title
Zammad: PGP signature spoofing via unvalidated verification return
Source: CVE Program / CVE List V5
Vulnerability Description
Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.2, summary In Zammad's inbound PGP email processing, the return value of the gpg verification call was silently discarded. Regardless of whether gpg reported a valid, invalid, or missing signature, the handler unconditionally wrote sign: { success: true, comment: "Good signature" } to the article's security preferences. Impact Any sender could tamper with the body of a multipart/signed PGP email, or craft a message with an entirely fabricated or mismatched signature, and Zammad would display it to the recipient as cryptographically verified with a "Good signature" label. Users and agents relying on Zammad's signature indicator to confirm message authenticity and integrity would be misled into trusting modified or forged content. The vulnerability affects all inbound PGP-signed emails processed while the PGP integration is enabled. This issue is fixed in version 7.0.2.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
认证机制不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
zammad zammad < 7.0.2 -

II. Public POCs for CVE-2026-56727

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III. Intelligence Information for CVE-2026-56727

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Other References for CVE-2026-56727 (3)

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-2026-84465 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-2026-56723 7.1 HIGH Zammad: Missing authorization on ticket attachment download
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-2026-56728 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-2026-63206 5.3 MEDIUM Zammad: Remote image tracking bypass via shortened URL scheme
CVE-2026-56734 5.3 MEDIUM Zammad: Avatar Image URL Server-Side Request Forwarding
CVE-2026-56732 5.3 MEDIUM Zammad: Malicious input in Ticket Body Enables Session Termination
CVE-2026-84460 5.3 MEDIUM Zammad: Missing Authorization in TagsController#list Allows Cross-Object Tag Enumeration
CVE-2026-61855 5.3 MEDIUM Zammad: Invalid PGP Detached Signatures Reported as Good Signature on Inbound Mail

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

IV. Related Vulnerabilities

Same product: zammad
Same vendor: zammad
Same weakness: CWE-287

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