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CVE-2026-40592— FreeScout's cross-user undo reply allows mailbox peers to recall another agent's outbound reply

Quick assessment

Affected

freescout-help-desk freescout

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.

FreeScout是FreeScout公司的一个使用 PHP（Laravel 框架）构建的超轻量级且功能强大的免费开源帮助台和共享收件箱。 FreeScout 1.8.214之前版本存在安全漏洞，该漏洞源于GET /conversation/undo-reply/{thread_id}路由仅检查当前用户是否可以查看父对话，未验证当前用户是否创建了要撤销的回复，可能导致在共享邮箱中，一个代理可以在15秒的撤销窗口内撤销另一个代理刚刚发送的回复。

CVSS 5.9 · Medium EPSS 0.24% · P15 Updated Apr 22, 2026

Possible ATT&CK Techniques 1 AI

T1078 · Valid Accounts

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I. Basic Information for CVE-2026-40592

Vulnerability Information

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Vulnerability Title

FreeScout's cross-user undo reply allows mailbox peers to recall another agent's outbound reply

Source: CVE Program / CVE List V5

Vulnerability Description

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.214, the undo-send route `GET /conversation/undo-reply/{thread_id}` checks only whether the current user can view the parent conversation. It does not verify that the current user created the reply being undone. In a shared mailbox, one agent can therefore recall another agent's just-sent reply during the 15-second undo window. Version 1.8.214 fixes the vulnerability.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L

Source: CVE Program / CVE List V5

Vulnerability Type

授权机制缺失

Source: CVE Program / CVE List V5

Vulnerability Title

FreeScout 安全漏洞

Source: CNNVD (China National Vulnerability Database)

Vulnerability Description

Source: CNNVD (China National Vulnerability Database)

CVSS Information

N/A

Source: CNNVD (China National Vulnerability Database)

Vulnerability Type

N/A

Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
freescout-help-desk	freescout	< 1.8.214	-

II. Public POCs for CVE-2026-40592

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-40592

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Vendor Advisories for CVE-2026-40592 (1)

🔗 Cross-user undo reply allows mailbox peers to recall another agent's outbound reply · Advisory · freescout-help-desk/freescout · GitHub Read full article x_refsource_CONFIRM

https://www.cve.org/CVERecord?id=CVE-2026-40592

Same Patch Batch · freescout-help-desk · 2026-04-21 · 20 CVEs total

CVE-2026-41193	9.1 CRITICAL	FreeScout has Zip Slip path traversal in module installation that allows arbitrary file wr
CVE-2026-40569	9.0 CRITICAL	FreeScout's Mass Assignment in Mailbox Connection Settings Enables Silent Email Exfiltrati
CVE-2026-40568	8.5 HIGH	FreeScout Vulnerable to XSS via Mailbox Signature Due to Incomplete HTML Sanitization
CVE-2026-40497	8.1 HIGH	FreeScout Vulnerable to CSS Injection via Stored Style Tag in Mailbox Signature (CSRF Toke
CVE-2026-40589	7.6 HIGH	FreeScout has Customer Edit Cross-Mailbox Email Takeover
CVE-2026-41190	7.1 HIGH	FreeScout has assigned-only visibility bypass via save_draft that allows hidden conversati
CVE-2026-41189	7.1 HIGH	FreeScout has assigned-only visibility bypass that allows editing hidden customer-authored
CVE-2026-41191	7.1 HIGH	FreeScout's signature only mailbox permission allows unauthorized mailbox chat setting cha
CVE-2026-40591	7.1 HIGH	FreeScout: Improper Authorization in Phone Conversation Creation Enables Cross-Mailbox Hid
CVE-2026-41192	7.1 HIGH	FreeScout's client-controlled attachment IDs allow deletion of existing conversation attac
CVE-2026-40565	6.1 MEDIUM	FreeScout has Stored XSS / CSS Injection via linkify() — Unescaped URL in Anchor href
CVE-2026-40567	5.8 MEDIUM	FreeScout has HTML Injection in Outgoing Emails via Unsanitized Customer Name in Signature
CVE-2026-41194	5.4 MEDIUM	FreeScout's Mailbox OAuth disconnect uses a state-changing GET and is CSRFable
CVE-2026-41183	4.3 MEDIUM	FreeScout allows non-folder conversation queries to disclose assigned-only hidden conversa
CVE-2026-40590	4.3 MEDIUM	FreeScout's Customer AJAX Create Modifies Hidden Existing Customer
CVE-2026-40566	4.1 MEDIUM	FreeScout vulnerable to SSRF via IMAP/SMTP Connection Test Endpoints
CVE-2026-40570		FreeScout's Missing Authorization in load_customer_info Allows Any Authenticated User to A
CVE-2026-40498		FreeScout has Authentication Bypass and Information Disclosure in SystemController via /sy
CVE-2026-40496		FreeScout has Predictable Attachment Token that Allows Unauthenticated Private File Downlo

IV. Related Vulnerabilities

Same product: freescout

Same vendor: freescout-help-desk

Same weakness: CWE-862