PHPStudy 2016-2018 Backdoor Remote Code Execution Vulnerability

published 2025-07-03 16 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-19906

cvss: 9.3; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.9%; EPSS 1.9% chance of exploitation in 30 days, percentile 80%
public exploits: 1; Metasploit

A backdoor in PHPStudy versions 2016 through 2018 allows unauthenticated remote attackers to execute arbitrary PHP code on affected installations. The backdoor listens for base64-encoded PHP payloads in the Accept-Charset HTTP header of incoming requests, decodes and executes the payload without proper validation. This leads to remote code execution as the web server user, compromising the affected system.

Timeline

2019-09-20 First public exploit (Metasploit exploit/multi/http/phpstudy_backdoor_rce)
2025-07-03 Published

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 16 mo ago (2025-07-07)

Exploit prediction

1.94% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

Metasploit exploit/multi/http/phpstudy_backdoor_rce PHPStudy Backdoor Remote Code execution metasploit exploit, excellent rank, 2019-09-20
raw.githubusercontent.com https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/multi/http/phpstudy_backdoor_rce.rb referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	9.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	9.3	CVSS: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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

Henan Xiaopi Security Technology Co., Ltd. PHPStudy

Classification

Weakness

CWE-94 Improper Control of Generation of Code

References

Sources

CVE List CVE-2025-34061
NVD CVE-2025-34061

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary