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CVE-2026-93634— Zimbra Collaboration Suite Cross-Account Authorization Bypass via Forged Shared-File Records

Quick assessment

Affected

Zimbra Zimbra Collaboration Suite

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.

Zimbra Collaboration Suite (ZCS) 中存在一个跨账户授权漏洞，该漏洞允许已认证用户通过 FileSharedWithMeRequest 接口，将伪造的共享文件记录插入到其他用户的邮箱中。该请求绕过了代理账户授权机制，在未验证是否存在对应文档共享的情况下，直接接受攻击者指定的文件元数据、所有者标识符及声明的文件大小。攻击者可以在目标账户未实际共享任何文档的情况下，植入归属于该真实本地账户的虚假记录。此攻击无需受害者进行任何交互。受影响版本包括 ZCS 10.1.16 和 10.1.20。

CVSS 4.3 · Medium Updated Oct 23, 2026

Possible ATT&CK Techniques 3 AI

T1190 · Exploit Public-Facing Application T1557 · Adversary-in-the-Middle T1098 · Account Manipulation

Affected Version Matrix 1

Vendor	Product	Version Range	Status
Zimbra	Zimbra Collaboration Suite	`≤ 10.1.20`	affected

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Vulnerability Information

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Vulnerability Title

Zimbra Collaboration Suite Cross-Account Authorization Bypass via Forged Shared-File Records

Source: CVE Program / CVE List V5

Vulnerability Description

A cross-account authorization vulnerability in Zimbra Collaboration Suite (ZCS) allows an authenticated user to insert forged shared-file records into another user's mailbox through FileSharedWithMeRequest. The request bypasses delegated-account authorization and accepts attacker-selected file metadata, owner identifiers and declared sizes without validating a corresponding document share. An attacker can plant entries attributed to another real local account without that account sharing a document. No victim interaction is required. ZCS 10.1.16 and 10.1.20 are affected.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A: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
Zimbra	Zimbra Collaboration Suite	0 ~ 10.1.20	-

II. Public POCs for CVE-2026-93634

#	POC Description	Source Link	Shenlong Link

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No public POC found.

III. Intelligence Information for CVE-2026-93634

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Vendor Advisories for CVE-2026-93634 (1)

Zimbra Security Advisories - Zimbra :: Tech Center vendor-advisory

Other References for CVE-2026-93634 (1)

https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/ related

https://www.cve.org/CVERecord?id=CVE-2026-93634

Same Patch Batch · Zimbra · 2026-10-23 · 17 CVEs total

CVE-2026-10632	8.7 HIGH	Zimbra Collaboration Suite Classic Web Client Reflected Cross-Site Scripting via Document
CVE-2026-50053	8.7 HIGH	Zimbra Collaboration Suite RestFilter Request Attribute Override via Unauthenticated URL P
CVE-2026-93639	8.7 HIGH	Zimbra Collaboration Suite Missing Authorization in ConfigureZimlet Enables Delegated Admi
CVE-2026-93640	7.8 HIGH	Zimbra Collaboration Suite Local Privilege Escalation via Unrestricted zmunbound Sudo Conf
CVE-2026-50056	7.8 HIGH	Zimbra Collaboration Suite Local Privilege Escalation via zmmailboxdmgr JVM Argument Injec
CVE-2026-50057	7.8 HIGH	Zimbra Collaboration Suite Local Privilege Escalation via Unrestricted Postfix Sudo Permis
CVE-2026-93631	7.1 HIGH	Zimbra Collaboration Suite OAuth Extension Cross-Site Request Forgery Enables Account Link
CVE-2026-115786	6.5 MEDIUM	Zimbra Collaboration Suite Shared-File Mailbox Quota Accounting Error Enables Quota Exhaus
CVE-2026-93638	6.1 MEDIUM	Zimbra Collaboration Suite Pre-Authentication Reflected Cross-Site Scripting via Login Pag
CVE-2026-93633	5.4 MEDIUM	Zimbra Collaboration Suite Briefcase CSS Sanitization Bypass via Non-ASCII Stylesheet Char
CVE-2026-93629	5.3 MEDIUM	Zimbra Collaboration Suite Calendar Processing Authentication Bypass via Forged iCalendar
CVE-2026-93627	5.3 MEDIUM	Zimbra Collaboration Suite Calendar Processing Authentication Bypass via Forged iCalendar
CVE-2026-93628	5.3 MEDIUM	Zimbra Collaboration Suite Calendar Processing Authentication Bypass via Forged iCalendar
CVE-2026-93630	4.3 MEDIUM	Zimbra Collaboration Suite Email HTML Sanitizer Bypass via Hostname Canonicalization
CVE-2026-93636	4.3 MEDIUM	Zimbra Collaboration Suite LDAP Filter Injection via Calendar Resource Attribute Name
CVE-2026-115785	4.3 MEDIUM	Zimbra Collaboration Suite Data Source Test SMTP Command Injection via Unsanitized Email A

IV. Related Vulnerabilities

Same product: Zimbra Collaboration Suite

Same vendor: Zimbra

Same weakness: CWE-639

V. Comments for CVE-2026-93634

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

CVE-2026-93634— Zimbra Collaboration Suite Cross-Account Authorization Bypass via Forged Shared-File Records

Quick assessment

Possible ATT&CK Techniques 3 AI

Affected Version Matrix 1

I. Basic Information for CVE-2026-93634

Vulnerability Information

Vulnerability Title

Vulnerability Description

CVSS Information

Vulnerability Type

Affected Products

II. Public POCs for CVE-2026-93634

III. Intelligence Information for CVE-2026-93634

Vendor Advisories for CVE-2026-93634 (1)

Other References for CVE-2026-93634 (1)

Same Patch Batch · Zimbra · 2026-10-23 · 17 CVEs total

IV. Related Vulnerabilities

V. Comments for CVE-2026-93634

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