CVE-2023-4739Public exploitNetwork attack vector

Authenticated code execution via unrestricted PHP upload

Published Sep 3, 2023 · Updated Nov 21, 2024

Unrestricted file upload in Byzoro Smart S85F Management Platform 20230820 allows remote authenticated users to execute PHP code. The updateos.php handler accepts a .php payload in the 1_file_upload multipart field and stores it beneath /home without blocking executable types. The published request requires a PHP session cookie, and the stored script runs when requested through the web server.

CVSS severity9.8
Critical
EPSS probability3.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in Byzoro Smart S85F Management Platform 20230820 allows remote authenticated users to execute PHP code. The updateos.php handler accepts a .php payload in the 1_file_upload multipart field and stores it beneath /home without blocking executable types. The published request requires a PHP session cookie, and the stored script runs when requested through the web server.

The record

CVE
CVE-2023-4739
Published
Sep 3, 2023
Updated
Nov 21, 2024
Vendor
Byzoro
Product
Smart S85F Management Platform
Classifications
CWE-434, T1505.003
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 3, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 21, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=20230820

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Byzoro · Smart S85F Management Platformversion=20230820

Published CVSS scores

9.8NVDCVSS: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.

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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-434Unrestricted Upload of File with Dangerous Type
T1505.003Server Software Component: Web Shell

Public exploit references

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

Technologies

Your stack

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Your stack

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