CVE-2026-40496— FreeScout has Predictable Attachment Token that Allows Unauthenticated Private File Download via Brute Force
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I. Basic Information for CVE-2026-40496
Vulnerability Information
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Vulnerability Title
FreeScout has Predictable Attachment Token that Allows Unauthenticated Private File Download via Brute Force
Source: NVD (National Vulnerability Database)
Vulnerability Description
FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, attachment download tokens are generated using a weak and predictable formula: `md5(APP_KEY + attachment_id + size)`. Since attachment_id is sequential and size can be brute-forced in a small range, an unauthenticated attacker can forge valid tokens and download any private attachment without credentials. Version 1.8.213 fixes the issue.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
使用不充分的随机数
Source: NVD (National Vulnerability Database)
Vulnerability Title
FreeScout 安全特征问题漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
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 1.8.213之前版本存在安全特征问题漏洞，该漏洞源于附件下载令牌使用弱且可预测的公式生成，可能导致未经身份验证的攻击者伪造有效令牌并下载任何私有附件。
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 | < 1.8.213 | - |
II. Public POCs for CVE-2026-40496
| # | POC Description | Source Link | Shenlong Link |
|---|
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- Release 1.8.213 · freescout-help-desk/freescout · GitHubx_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2026-40496
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-2026-41192 | 7.1 HIGH | FreeScout's client-controlled attachment IDs allow deletion of existing conversation attac |
| CVE-2026-40591 | 7.1 HIGH | FreeScout: Improper Authorization in Phone Conversation Creation Enables Cross-Mailbox Hid |
| CVE-2026-40565 | 6.1 MEDIUM | FreeScout has Stored XSS / CSS Injection via linkify() — Unescaped URL in Anchor href |
| CVE-2026-40592 | 5.9 MEDIUM | FreeScout's cross-user undo reply allows mailbox peers to recall another agent's outbound |
| 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 |
IV. Related Vulnerabilities
Same product: freescout
- CVE-2026-41906
FreeScout: Conversation Change-Customer Cross-Mailbox Author - CVE-2026-41905
FreeScout vulnerable to SSRF via Helper::sanitizeRemoteUrl: - CVE-2026-41904
FreeScout Stored XSS vulnerability in mailbox auto-reply: pa - CVE-2026-41902
FreeScout's user invitation hash never expires: permanent un - CVE-2026-41903
FreeScout IDOR Vulnerability: PERM_EDIT_USERS allows modifyi
Same vendor: freescout-help-desk
- CVE-2026-41906
FreeScout: Conversation Change-Customer Cross-Mailbox Author - CVE-2026-41905
FreeScout vulnerable to SSRF via Helper::sanitizeRemoteUrl: - CVE-2026-41904
FreeScout Stored XSS vulnerability in mailbox auto-reply: pa - CVE-2026-41902
FreeScout's user invitation hash never expires: permanent un - CVE-2026-41903
FreeScout IDOR Vulnerability: PERM_EDIT_USERS allows modifyi
Same weakness: CWE-330
- CVE-2026-7847
chatchat-space Langchain-Chatchat Uploaded File openai_route - CVE-2026-40975
VMware Spring Boot 安全特征问题漏洞 - CVE-2026-40306
DNN has same HostGUID for all new installs - CVE-2026-33710
Chamilo LMS has Weak REST API Key Generation (Predictable) - CVE-2026-34511
OpenClaw < 2026.4.2 - PKCE Verifier Exposure via OAuth State
V. Comments for CVE-2026-40496
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