How severe is CVE-2025-9133?

CVE-2025-9133 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2025-9133 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-9133?

CVE-2025-9133 affects Zyxel Zld. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-9133?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-9133 have an EU (EUVD) identifier?

Yes. CVE-2025-9133 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-35119.

When was CVE-2025-9133 published?

CVE-2025-9133 was published on 2025-10-21 and last updated on 2026-06-17.

CVE-2025-9133

CVE-2025-9133 is a high-severity vulnerability in Zyxel Zld with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-862.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 5% (93rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-35119
Weakness: CWE-862
Affected product: Zyxel Zld
Published: 2025-10-21
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2025-9133?: 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.
How severe is CVE-2025-9133?: CVE-2025-9133 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2025-9133 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-9133?: CVE-2025-9133 affects Zyxel Zld. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-9133?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-9133 have an EU (EUVD) identifier?: Yes. CVE-2025-9133 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-35119.
When was CVE-2025-9133 published?: CVE-2025-9133 was published on 2025-10-21 and last updated on 2026-06-17.

References

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-post-authentication-command-injection-and-missing-authorization-vulnerabilities-in-zld-firewalls-10-21-2025

Affected products (1)

cpe:2.3:o:zyxel:zld:*:*:*:*:*:*:*:*

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