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CVE-2025-54366VulnerabilityPublished Updated

CVE-2025-54366: freescout · Deserialization of Untrusted Data

Affects freescoutSource CVE Database V5

0

Not known to be exploited · CVSS 8.6 High : upgrade to 1.8.186 soon.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score
8.6High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
1.0% chance of exploitation in 30 days – higher than 64% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.8.186
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 26 Jul 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

Upgrade freescout-help-desk/freescout to 1.8.186.

Affected software

ProductAffectedFixed in
GitHubfreescout-help-desk/freescoutpkg:github/freescout-help-desk/freescoutOther threatsAffected
  • <1.8.186
Fixed in
  • 1.8.186

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

1. Immediate upgrade to FreeScout version 1.8.186 or later, where the vulnerability is patched, is the most effective mitigation. 2. Restrict access to the /conversation/ajax endpoint to trusted users and networks, employing network segmentation and firewall rules to limit exposure. 3. Securely manage and rotate the APP_KEY to prevent unauthorized knowledge or reuse of compromised keys. 4. Implement strict authentication and authorization controls to minimize the risk of credential compromise. 5. Monitor application logs and network traffic for unusual activity related to deserialization or unexpected POST requests to the vulnerable endpoint. 6. Conduct regular security audits and penetration testing focusing on deserialization and input validation weaknesses. 7. If upgrading immediately is not feasible, consider applying web application firewall (WAF) rules to detect and block suspicious serialized payloads targeting the attachments parameters. 8. Educate developers and administrators about secure coding practices, especially regarding deserialization and cryptographic key management.

Description

FreeScout is a lightweight free open source help desk and shared inbox built with PHP (Laravel framework). In versions 1.8.185 and below, there is a critical deserialization vulnerability in the /conversation/ajax endpoint that allows authenticated users with knowledge of the APP_KEY to achieve remote code execution. The vulnerability occurs when the application processes the attachments_all and attachments POST parameters through the insecure Helper::decrypt() function, which performs unsafe deserialization of user-controlled data without proper validation. This flaw enables attackers to create arbitrary objects and manipulate their properties, leading to complete compromise of the web application. This is fixed in version 1.8.186.

References

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