Strix
26.1K

CVE-2025-34061

CRITICALCVSS 9.3/10EPSS 1.17%

Last modified

CVE-2025-34061 is a critical-severity vulnerability rated 9.3/10 on the CVSS scale. 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. EPSS estimates a 1.17% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 4.0
9.3/10

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

EPSS Probability
1.17%

63.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2025-34061?
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.
How severe is CVE-2025-34061?
CVE-2025-34061 has a CVSS score of 9.3/10 (CRITICAL severity). The EPSS model estimates a 1.17% probability of exploitation in the next 30 days.
How do I fix CVE-2025-34061?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-34061?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST