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CVE-2025-9133· NVD / CVE Program· CNA Zyxel

A missing authorization vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.40, USG FLEX series firmware versions from

Noroxi assessment

Priority: Monitor (action score 34/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 5.4% (FIRST EPSS); higher than 92.6% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

A missing authorization vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.40, USG FLEX series firmware versions from V4.50 through V5.40, USG FLEX 50(W) series firmware versions from V4.16 through V5.40, and USG20(W)-VPN series firmware versions from V4.16 through V5.40 could allow a semi-authenticated attacker—who has completed only the first stage of the two-factor authentication (2FA) process—to view and download the system configuration from an affected device.

HighCVSS 8.1 · v3.1—No exploit No fix recorded
Published
Oct 21, 2025
Updated
Oct 18, 2026
EPSS
5.4% · 92th percentile

Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
32 / 40 · 8.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
2 / 30 · 5.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Zyxel
8.1
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-9133

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
zyxelzld
zyxelatp100
zyxelatp100w
zyxelatp200
zyxelatp500
zyxelatp700
zyxelatp800
zyxelusg flex 100
zyxelusg flex 100ax
zyxelusg flex 100w
zyxelusg flex 200
zyxelusg flex 50

and 5 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • zyxel zld4.32 and later · before 5.41
  • zyxel zld4.50 and later · before 5.41
  • zyxel zld4.16 and later · before 5.41

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Zyxel). Independent of NVD's CPE analysis and usually ahead of it.

  • Zyxel ATP series firmware

    • versions from V4.32 through V5.40affected

  • Zyxel USG FLEX 50(W) series firmware

    • versions from V4.16 through V5.40affected

  • Zyxel USG FLEX series firmware

    • versions from V4.50 through V5.40affected

  • Zyxel USG20(W)-VPN series firmware

    • versions from V4.16 through V5.40affected

Same product

zyxel: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-11667A directory traversal vulnerability in the web management interface of Zyxel ATP series firmware versions V5.00 through V5.38, USG FLEX seriKEV
    70This week
  • CVE-2020-25014A stack-based buffer overflow in fbwifi_continue.cgi on Zyxel UTM and VPN series of gateways running firmware version V4.30 through to V4.55
    40Plan
  • CVE-2024-42057A command injection vulnerability in the IPSec VPN feature of Zyxel ATP series firmware versions from V4.32 through V5.38, USG FLEX series f
    32Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2024-7203Sep 2, 2024 · A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V4.60 through V5.38 and USG FLEX series fir
    28Monitor
  • ← EarlierCVE-2024-42061Sep 2, 2024 · A reflected cross-site scripting (XSS) vulnerability in the CGI program "dynamic_script.cgi" of Zyxel ATP series firmware versions from V4.3
    24Monitor
  • ← EarlierCVE-2025-8078Oct 21, 2025 · A post-authentication command injection vulnerability in Zyxel ATP series firmware versions from V4.32 through V5.40, USG FLEX series firmwa
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-862 · Missing Authorization

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records