How severe is CVE-2023-6398?

CVE-2023-6398 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2023-6398 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-6398?

CVE-2023-6398 primarily affects Zyxel Atp100 Firmware. In total, 85 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-6398?

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-2023-6398 have an EU (EUVD) identifier?

Yes. CVE-2023-6398 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-58635.

When was CVE-2023-6398 published?

CVE-2023-6398 was published on 2024-02-20 and last updated on 2026-06-17.

CVE-2023-6398

CVE-2023-6398 is a high-severity vulnerability in Zyxel Atp100 Firmware with a CVSS 3.x base score of 7.2. 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-78.

Key facts

Severity: High (CVSS 3.x base score 7.2)
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2023-58635
Weakness: CWE-78
Affected product: Zyxel Atp100 Firmware
Published: 2024-02-20
Last modified: 2026-06-17

Description

A post-authentication command injection vulnerability in the file upload binary in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch 1, USG FLEX series firmware versions from 4.50 through 5.37 Patch 1, USG FLEX 50(W) series firmware versions from 4.16 through 5.37 Patch 1, USG20(W)-VPN series firmware versions from 4.16 through 5.37 Patch 1, USG FLEX H series firmware versions from 1.10 through 1.10 Patch 1, NWA50AX firmware versions through 6.29(ABYW.3), WAC500 firmware versions through 6.65(ABVS.1), WAX300H firmware versions through 6.60(ACHF.1), and WBE660S firmware versions through 6.65(ACGG.1) could allow an authenticated attacker with administrator privileges to execute some operating system (OS) commands on an affected device via FTP.

Frequently asked questions

What is CVE-2023-6398?: A post-authentication command injection vulnerability in the file upload binary in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch 1, USG FLEX series firmware versions from 4.50 through 5.37 Patch 1, USG FLEX 50(W) series firmware versions from 4.16 through 5.37 Patch 1, USG20(W)-VPN series firmware versions from 4.16 through 5.37 Patch 1, USG FLEX H series firmware versions from 1.10 through 1.10 Patch 1, NWA50AX firmware versions through 6.29(ABYW.3), WAC500 firmware versions through 6.65(ABVS.1), WAX300H firmware versions through 6.60(ACHF.1), and WBE660S firmware versions through 6.65(ACGG.1) could allow an authenticated attacker with administrator privileges to execute some operating system (OS) commands on an affected device via FTP.
How severe is CVE-2023-6398?: CVE-2023-6398 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2023-6398 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-6398?: CVE-2023-6398 primarily affects Zyxel Atp100 Firmware. In total, 85 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-6398?: 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-2023-6398 have an EU (EUVD) identifier?: Yes. CVE-2023-6398 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-58635.
When was CVE-2023-6398 published?: CVE-2023-6398 was published on 2024-02-20 and last updated on 2026-06-17.

References

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-aps-02-20-2024

Affected products (85)

cpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100w_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp100w_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp200_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp200_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp500_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp500_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp700_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp700_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp700_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp800_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp800_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:atp800_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100ax_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100ax_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100ax_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100h_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100h_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100h_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100w_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100w_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_100w_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200h_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200h_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200h_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200hp_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200hp_firmware:5.37:-:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_200hp_firmware:5.37:patch1:*:*:*:*:*:*
cpe:2.3:o:zyxel:usg_flex_50_firmware:*:*:*:*:*:*:*:*

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