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Freescout CVE-2026-34442

| EUVDEUVD-2026-17673 MEDIUM
Improper Input Validation (CWE-20)
2026-03-31 GitHub_M
6.1
CVSS 3.1 · NVD
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V2 - Validation and Business Logic Input validation, allowlisting
Impact

CVSS vector (AV:N/AC:L/PR:N/UI:R) indicates network-accessible, low-complexity exploitation requiring no privileges but mandating user interaction. EPSS score not provided, limiting exploitation probability assessment. No public exploit code or CISA KEV status reported, suggesting this is a confirmed but not yet weaponized vulnerability. The requirement for UI interaction (user clicking a malicious link) significantly reduces real-world impact compared to a CVSS 5.4 with UI:N. Threat model depends on help desk context: attacks targeting support staff or end-users via phishing emails containing FreeScout-generated links are plausible. The vulnerability affects all versions prior to 1.8.211, making it a patch-worthy priority but not a critical 0-day. Organizations running exposed FreeScout instances should prioritize patching, particularly if user-facing.

Exploit ScenarioDerived

An attacker sends a help desk support request containing a crafted FreeScout URL with a malicious Host header (e.g., 'Host: evil.com'), or crafts a link to /system/status with Host manipulation. When a support staff member or customer clicks a generated password reset link or accesses the system status page, the application constructs absolute URLs using the attacker-controlled Host header value, redirecting the user to attacker.com. Alternatively, if FreeScout generates email notification links based on the Host header, the attacker can include a malicious Host in the initial request, causing the application to send emails with links pointing to attacker infrastructure. No public exploit code has been identified, but the attack requires only HTTP request crafting and user-interaction execution.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 31, 2026

Host header manipulation in FreeScout prior to version 1.8.211 allows unauthenticated remote attackers to inject arbitrary domains into application-generated absolute URLs, enabling open redirects and external resource loading attacks. The vulnerability exploits unvalidated Host header values to construct malicious links and asset references, potentially redirecting users to attacker-controlled domains or loading external resources from compromised servers. CVSS 5.4 reflects low-to-moderate real-world risk given the requirement for user interaction (UI:R), though no active exploitation has been publicly confirmed.

RemediationAI

Vendor-released patch: FreeScout 1.8.211. Upgrade immediately from the official GitHub releases page at https://github.com/freescout-help-desk/freescout/releases/tag/1.8.211. For organizations unable to upgrade immediately, implement a reverse proxy or WAF rule to validate and restrict the Host header to expected domain values only, preventing arbitrary domain injection. Verify that email notifications and system status pages (such as /system/status) are not exposing user-controllable URLs after patching. Audit logs for suspicious Host header values in prior access patterns.

Affected VersionsENISA

freescout < 1.8.211

Affected Packages

euvd freescout fix: 1.8.211

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

FreeScout is a Laravel-based PHP help desk application that dynamically constructs absolute URLs for links and assets using the HTTP Host header without proper validation. The root cause is improper input validation (CWE-20) of untrusted HTTP headers. Laravel applications commonly use the Host header to generate base URLs for email notifications, password reset links, and front-end asset references. When an attacker crafts a request with a manipulated Host header (e.g., 'Host: attacker.com'), the application incorporates this value into generated URLs, bypassing SAME_SITE protections and enabling open redirect vulnerabilities. This is particularly dangerous in help desk contexts where generated links are shared via email or displayed in system status pages, increasing user trust and click-through likelihood.

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Severity by source

NVD PRIMARY 6.1 MEDIUM
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

Lifecycle Timeline

3
CVSS changed
Jul 24, 2026 - 21:22 NVD
5.4 (MEDIUM) 6.1 (MEDIUM)
Patch available
Apr 16, 2026 - 05:29 EUVD
1.8.211
CVE Published
Mar 31, 2026 - 21:28 nvd
MEDIUM 5.4

DescriptionNVD

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.211, host header manipulation in FreeScout version (http://localhost:8080/system/status) allows an attacker to inject an arbitrary domain into generated absolute URLs. This leads to External Resource Loading and Open Redirect behavior. When the application constructs links and assets using the unvalidated Host header, user requests can be redirected to attacker-controlled domains and external resources may be loaded from malicious servers. This issue has been patched in version 1.8.211.

Threat Intelligence Overview

EPSS Score
0.0%
Top 88% exploitable
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment GitHub VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
Poc
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

30
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +30
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0
CVE-2026-28289 CRITICAL POC
10.0 Mar 03

File upload bypass in FreeScout 1.8.206 — patch bypass for CVE-2026-27636. PoC and patch available. CVSS 10.0.

CVE-2026-27636 HIGH POC
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CVE-2026-27637 CRITICAL POC
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CVE-2026-53595 CRITICAL POC
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CVE-2025-58163 HIGH POC
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CVE-2024-28186 HIGH POC
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CVE-2024-34698 MEDIUM POC
6.3 May 14

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CVE-2024-34697 MEDIUM POC
6.1 May 14

FreeScout is a free, self-hosted help desk and shared mailbox. Rated medium severity (CVSS 6.1), this vulnerability is r

CVE-2026-32754 CRITICAL
9.3 Mar 19

A stored cross-site scripting (XSS) vulnerability exists in FreeScout help desk software versions 1.8.208 and below, whe

CVE-2026-41193 CRITICAL
9.1 Apr 21

Arbitrary file write in FreeScout (prior to 1.8.215) allows authenticated administrators to achieve remote code executio

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