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.
CVE-2025-54366
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).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- 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 computedSeverity88% × 45%Exploitation40% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 58.5%
- KEV
- Not listed
Published
July 26, 2025
Last Modified
September 11, 2025
References (2)
- security-advisories@githubhttps://github.com/freescout-help-desk/freescout/commit/9669c57f1ddbee896752d9e16270abfd97b20eb9
- security-advisories@githubhttps://github.com/freescout-help-desk/freescout/security/advisories/GHSA-vcc2-6r66-gvvj
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 12× in last 7d / 44× 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.
- 2026-07-25 14:17 UTCEPSS rescore
- 2026-07-24 14:17 UTCEPSS rescore
- 2026-07-24 00:11 UTCOSV refresh
- 2026-07-23 14:18 UTCEPSS rescore
- 2026-07-23 02:58 UTCEG score recompute
- 2026-07-22 14:08 UTCEPSS rescore
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- 2026-07-08 15:15 UTCEPSS rescore
- 2026-07-07 13:45 UTCEPSS rescore
- 2026-07-06 18:21 UTCOSV refresh
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- 2026-06-19 19:25 UTCEPSS rescore
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- 2026-06-18 17:52 UTCEPSS rescore
- 2026-06-18 17:52 UTCEPSS rescore
- 2026-06-18 06:35 UTCOSV refresh
- 2026-06-17 17:52 UTCEPSS rescore
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- 2026-06-08 14:16 UTCEPSS rescore
- 2026-06-07 15:24 UTCEPSS rescore
- 2026-06-07 15:24 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
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- 2026-06-05 22:46 UTCEPSS rescore
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- 2026-06-05 06:10 UTCEPSS rescore
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- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-02 20:12 UTCEPSS rescore
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- 2026-06-01 13:51 UTCEPSS rescore
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- 2026-05-31 22:30 UTCEPSS rescore
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- 2026-05-31 00:16 UTCEPSS rescore
- 2026-05-31 00:16 UTCEPSS rescore
- 2026-05-30 01:17 UTCEG score recompute
- 2026-05-29 13:44 UTCEPSS rescore
Related CVEs(same CWE)
Same CWE
10 shownCWE-502
- CVE-2017-20208EG 9.8CRITICAL
- CVE-2017-20207EG 9.8CRITICAL
- CVE-2017-20206EG 9.8CRITICAL
- CVE-2017-20189EG 9.8CRITICAL
- CVE-2017-10992EG 9.8EPSS 95%CRITICAL
- CVE-2013-4521EG 9.8EPSS 90%CRITICAL
- CVE-2014-1860EG 9.8CRITICAL
- CVE-2016-1000027EG 9.8EPSS 98%CRITICAL
- CVE-2014-3699EG 9.8CRITICAL
- CVE-2017-18605EG 9.8CRITICAL
Frequently asked(5)
What is CVE-2025-54366?
When was CVE-2025-54366 disclosed?
Is CVE-2025-54366 actively exploited?
What is the CVSS score of CVE-2025-54366?
How do I remediate CVE-2025-54366?
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2025-54366
Is Your Infrastructure Affected by CVE-2025-54366?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.