CVE-2025-9133Network attack vector

Configuration disclosure via incomplete 2FA authorization

Published Oct 21, 2025 · Updated Oct 21, 2025

Missing authorization in Zyxel ZLD firewall firmware allows remote authenticated users to download system configurations from affected devices. An unspecified configuration-download request accepts a session after only the first stage of two-factor authentication instead of requiring completion of the second stage. Access therefore requires valid first-stage credentials, and the demonstrated consequence is disclosure of the device configuration; Zyxel has not published the affected endpoint or authorization-check implementation.

CVSS severity8.1
High
EPSS probability5.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Zyxel ZLD firewall firmware allows remote authenticated users to download system configurations from affected devices. An unspecified configuration-download request accepts a session after only the first stage of two-factor authentication instead of requiring completion of the second stage. Access therefore requires valid first-stage credentials, and the demonstrated consequence is disclosure of the device configuration; Zyxel has not published the affected endpoint or authorization-check implementation.

The record

CVE
CVE-2025-9133
Published
Oct 21, 2025
Updated
Oct 21, 2025
Vendor
Zyxel Networks
Product
USG20(W)-VPN Series
Classifications
CWE-862
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 21, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 21, 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=versions from V4.16 through V5.40

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zyxel Networks · USG20(W)-VPN Seriesversion=versions from V4.16 through V5.40
Zyxel Networks · USG FLEX 50 Seriesversion=versions from V4.16 through V5.40
Zyxel Networks · ATP Seriesversion=versions from V4.32 through V5.40
Zyxel Networks · USG FLEX Seriesversion=versions from V4.50 through V5.40

Published CVSS scores

8.1Zyxel CorporationCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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