CVE-2021-35370Public exploitNetwork attack vector

Authenticated code execution via source-editor filter bypass

Published Feb 24, 2023 · Updated Mar 12, 2025

Code execution in Peacexie Imcat 5.4 allows remote authenticated users to execute arbitrary PHP through the built-in source editor. safscan.php applies an incomplete dangerous-function filter that can be bypassed by concatenating strings to construct assert, after which the editor saves executable PHP. Access to the CMS background and source-editing function is required; successful exploitation runs code with the web server account and can create a web shell.

CVSS severity9.8
Critical
EPSS probability1.03%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Code execution in Peacexie Imcat 5.4 allows remote authenticated users to execute arbitrary PHP through the built-in source editor. safscan.php applies an incomplete dangerous-function filter that can be bypassed by concatenating strings to construct assert, after which the editor saves executable PHP. Access to the CMS background and source-editing function is required; successful exploitation runs code with the web server account and can create a web shell.

The record

CVE
CVE-2021-35370
Published
Feb 24, 2023
Updated
Mar 12, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-20, T1505.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 12, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
T1505.003Web Shell

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo