SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-67399

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.

CRITICAL 9.3EPSS 0.69%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.69%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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.

CVSS 4.0
9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.69% probability · 51th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-502
Source
support@hackerone.com
EPSS trend
0%3%5%19 September 2026: 0.69%19 September 202619 September 2026

EPSS 0.7% since 19 September 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.