CVE-2023-4739
Byzoro Smart S85F Firmware ≤ 20230820
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:LSummary
CVE-2023-4739 is a medium-severity Unrestricted Upload of File with Dangerous Type (CWE-434) vulnerability in Byzoro Smart S85F Firmware. Its CVSS base score is 6.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 14% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
A critical vulnerability exists in the Byzoro Smart S85F Management Platform up to 20230820 within the /sysmanage/updateos.php file. Unrestricted upload of files with dangerous types occurs through manipulation of the 1_file_upload argument, corresponding to CWE-434. The flaw can be reached remotely and carries a CVSS 3.1 score of 6.3.
An authenticated attacker with low privileges can send a crafted request to upload arbitrary files to the server. Successful exploitation grants limited control over confidentiality, integrity, and availability of the affected system. Public exploit code has been released, and the vendor did not respond to early disclosure notification.
EPSS for the CVE rose materially from a low baseline to a peak of 0.0583 on 2025-01-22 before receding, indicating that exploitation interest developed well after the original publication. No vendor advisories or patches are referenced in available sources.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-54587
Vulnerability Data
A vulnerability, which was classified as critical, has been found in Byzoro Smart S85F Management Platform up to 20230820. Affected by this issue is some unknown functionality of the file /sysmanage/updateos.php. The manipulation of the argument 1_file_upload leads to unrestricted…
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upload. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-238628. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.1.1
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Requiring identifiable owners for portable devices reduces the attack surface for unrestricted uploads of dangerous file types via anonymous media.
Dangerous file uploads can be detonated in the chamber to determine malice before any production write or execution occurs.
Prevents unrestricted writing of arbitrary or malicious firmware by keeping hardware write-protect enabled except under tightly controlled manual procedures.
Scans files from external sources on download/open/execute, blocking unrestricted uploads of dangerous file types.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Restricting execution of unauthorized software directly blocks dangerous uploaded files from running.
Hardened configuration baselines can enforce allowed file types and processing rules.
Secure development practices include input validation and file-type restrictions that prevent this weakness.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Configuration and acceptance testing verify that file-upload handling enforces allowed types and does not permit dangerous content to be stored or executed.
Secure-coding guidelines and security testing explicitly address restrictions on allowed file types and upload handling, reducing the risk that dangerous file uploads are accepted without validation.
Mandated testing for malicious content and known vulnerabilities reduces the likelihood that an outsourced component will contain or accept dangerous file types that could later be uploaded or executed.
Application allow-listing and pre-use scanning of received files directly blocks the introduction of executable content that has not been vetted, eliminating the primary vector for unrestricted dangerous file uploads.