CVE-2025-54366

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.8 under NVD CVSS v3. EPSS exploit probability: 1.0%, top 42% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.8Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
8.8
EG Score
8.8(medium)
EG Risk
56(Track)
EG Risk 56/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity88% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
61%
KEV
Not listed

Published

July 26, 2025

Last Modified

September 11, 2025

Advisory Details (2)

Auto-updated Aug 31, 2026
Patch available. Sources: github_commit, github.
github Patch Available

Deserialization of untrusted data leads to Remote code execution (RCE) [9] · Advisory · freescout-help-desk/freescout · GitHub

https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-vcc2-6r66-gvvj
github_commit Patch Available

commit 9669c57f1ddb (freescout-help-desk/freescout)

Patch available: freescout-help-desk/freescout 1.8.209 (contains commit 9669c57f1ddb)

https://github.com/freescout-help-desk/freescout/commit/9669c57f1ddbee896752d9e16270abfd97b20eb9

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 32× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 154 total refreshes for this CVE.

  1. 2026-09-20 20:15 UTCEPSS rescore
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  1. 2026-08-27 14:24 UTCEPSS rescore
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  4. 2026-08-25 07:26 UTCOSV refresh
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  22. 2026-08-09 01:19 UTCOSV refresh
  23. 2026-08-08 16:36 UTCEPSS rescore
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  39. 2026-07-24 00:11 UTCOSV refresh
  40. 2026-07-23 14:18 UTCEPSS rescore
  41. 2026-07-23 02:58 UTCEG score recompute
  42. 2026-07-22 14:08 UTCEPSS rescore
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  65. 2026-07-06 16:27 UTCEPSS rescore
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  73. 2026-06-30 23:22 UTCEPSS rescore
  74. 2026-06-29 14:06 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2025-54366?
CVE-2025-54366 is a high vulnerability published on July 26, 2025. 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 APPKEY to achieve…
When was CVE-2025-54366 disclosed?
CVE-2025-54366 was first published in the National Vulnerability Database on July 26, 2025, with the most recent update on September 11, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-54366 actively exploited?
CVE-2025-54366 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 39.4% of all scored CVEs.
What is the CVSS score of CVE-2025-54366?
CVE-2025-54366 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2025-54366?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-54366, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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