CVE-2020-23591Network attack vector

Unauthenticated code execution via unrestricted firmware upload

Published Nov 23, 2022 · Updated Apr 29, 2025

Unrestricted file upload in OPTILINK OP-XT71000N firmware 3.3.1-191028 allows remote attackers to execute code via crafted files. The /mgm_dev_upgrade.asp handler accepts arbitrary file types, including executable ASP web shells, without restricting dangerous uploads. No authentication or user interaction is required, and uploaded code can establish a backdoor or delete files to interrupt the device.

CVSS severity9.8
Critical
EPSS probability1.07%
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 OPTILINK OP-XT71000N firmware 3.3.1-191028 allows remote attackers to execute code via crafted files. The /mgm_dev_upgrade.asp handler accepts arbitrary file types, including executable ASP web shells, without restricting dangerous uploads. No authentication or user interaction is required, and uploaded code can establish a backdoor or delete files to interrupt the device.

The record

CVE
CVE-2020-23591
Published
Nov 23, 2022
Updated
Apr 29, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-434, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 23, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 29, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NIST NVDCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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