CVE-2022-45440

Root filesystem read via FTP symlink following

Published Jan 17, 2023 · Updated Dec 17, 2025

Improper link resolution in Zyxel AX7501-B0 firmware before V5.17(ABPC.3)C0 allows local users to read the root file system. The device's FTP server follows a symbolic link placed on external storage, exposing its target outside the storage volume when an FTP session retrieves it. Exploitation requires administrator credentials, physical placement of media such as a USB flash drive, and an FTP login; the reported consequence is read access only.

CVSS severity4.4
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper link resolution in Zyxel AX7501-B0 firmware before V5.17(ABPC.3)C0 allows local users to read the root file system. The device's FTP server follows a symbolic link placed on external storage, exposing its target outside the storage volume when an FTP session retrieves it. Exploitation requires administrator credentials, physical placement of media such as a USB flash drive, and an FTP login; the reported consequence is read access only.

The record

CVE
CVE-2022-45440
Published
Jan 17, 2023
Updated
Dec 17, 2025
Vendor
Zyxel Networks
Product
AX7501-B0 Firmware
Classifications
CWE-59, T1005
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jan 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Dec 17, 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?

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

  1. Affected versionversion=< V5.17(ABPC.3)C0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Zyxel Networks · AX7501-B0 Firmwareversion=< V5.17(ABPC.3)C0

Published CVSS scores

4.4Zyxel CorporationCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

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)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-59Improper Link Resolution Before File Access ('Link Following')
T1005Data from Local System

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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