Deserialization of untrusted data in WHMCS 9.0.0 before 9.0.8 and 8.0.0 before 8.13.7 allows remote attackers to execute arbitrary code. (CVE-2026-67399)
A critical vulnerability in WHMCS versions 9.0.0 before 9.0.8 and 8.0.0 before 8.13.7 allows remote attackers to execute arbitrary code via deserialization of untrusted data.
AI Analysis
Technical Summary
CVE-2026-67399 is a deserialization vulnerability in WHMCS that affects versions 9.0.0 prior to 9.0.8 and 8.0.0 prior to 8.13.7. This flaw allows remote attackers to execute arbitrary code on the affected systems by exploiting unsafe deserialization of untrusted data. The vulnerability is classified under CWE-502 (Deserialization of Untrusted Data).
Potential Impact
Successful exploitation enables remote attackers to execute arbitrary code without authentication, potentially leading to full system compromise. The vulnerability is critical due to its remote code execution capability and lack of required privileges or user interaction.
Mitigation Recommendations
Apply the official patches by upgrading WHMCS to version 9.0.8 or later for the 9.x branch, or 8.13.7 or later for the 8.x branch. Patch status is confirmed by the version boundaries in the description. No additional mitigation guidance is provided.
Deserialization of untrusted data in WHMCS 9.0.0 before 9.0.8 and 8.0.0 before 8.13.7 allows remote attackers to execute arbitrary code. (CVE-2026-67399)
Description
A critical vulnerability in WHMCS versions 9.0.0 before 9.0.8 and 8.0.0 before 8.13.7 allows remote attackers to execute arbitrary code via deserialization of untrusted data.
CVSS v4.0
Affected software
pkg:composer/whmcs/whmcsRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-67399 is a deserialization vulnerability in WHMCS that affects versions 9.0.0 prior to 9.0.8 and 8.0.0 prior to 8.13.7. This flaw allows remote attackers to execute arbitrary code on the affected systems by exploiting unsafe deserialization of untrusted data. The vulnerability is classified under CWE-502 (Deserialization of Untrusted Data).
Potential Impact
Successful exploitation enables remote attackers to execute arbitrary code without authentication, potentially leading to full system compromise. The vulnerability is critical due to its remote code execution capability and lack of required privileges or user interaction.
Mitigation Recommendations
Apply the official patches by upgrading WHMCS to version 9.0.8 or later for the 9.x branch, or 8.13.7 or later for the 8.x branch. Patch status is confirmed by the version boundaries in the description. No additional mitigation guidance is provided.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-5jq9-2qvc-rc4h
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-67399"]
- Database Specific Severity
- CRITICAL
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6aa8a1aa55bf5e2cf5f3d550
Added to database: 09/15/2026, 01:38:50 UTC
Last enriched: 09/15/2026, 01:53:11 UTC
Last updated: 09/15/2026, 05:01:27 UTC
Views: 5
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