CVE-2023-27991

highpriority · track · 36EPSS 0.015 · 73 %ileDEEURUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

1.45% (73rd) EPSS

CVSS 8.8 · high

Is it mine?

43 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-27

The post-authentication command injection vulnerability in the CLI command of Zyxel ATP series firmware versions 4.32 through 5.35, USG FLEX series firmware versions 4.50 through 5.35, USG FLEX 50(W) firmware versions 4.16 through 5.35, USG20(W)-VPN firmware versions 4.16 through 5.35, and VPN series firmware versions 4.30 through 5.35, which could allow an authenticated attacker to execute some OS commands remotely.

cvss

Technical severity, 0–10. One row per scoring source.

8.8

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.8 · impact 5.9

v3.18.8highAV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · security@zyxel.com.twexploitability 2.8 · impact 5.9

v3.18.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-78USprimaryCWE-79US

affected products (43)

Products and version ranges known to be affected.

Zyxel ATP series firmware≤ 4.32 through 5.35enisa_euvdEU
Zyxel USG FLEX 50(W) firmware≤ 4.16 through 5.35enisa_euvdEU
Zyxel USG FLEX series firmware≤ 4.50 through 5.35enisa_euvdEU
Zyxel USG20(W)-VPN firmware≤ 4.16 through 5.35enisa_euvdEU
Zyxel VPN series Firmware≤ 4.30 through 5.35enisa_euvdEU
Zyxel Communications Corp. ATP1004.32 → 5.36fstec_bduRU
Zyxel Communications Corp. ATP100W4.32 → 5.36fstec_bduRU
Zyxel Communications Corp. ATP2004.32 → 5.36fstec_bduRU
Zyxel Communications Corp. ATP5004.32 → 5.36fstec_bduRU
Zyxel Communications Corp. ATP7004.32 → 5.36fstec_bduRU
Zyxel Communications Corp. ATP8004.32 → 5.36fstec_bduRU
Zyxel Communications Corp. USG 100-VPN4.30 → 5.36fstec_bduRU
Zyxel Communications Corp. USG 20-VPN4.30 → 5.36fstec_bduRU
Zyxel Communications Corp. USG FLEX 1004.50 → 5.36fstec_bduRU
Zyxel Communications Corp. USG FLEX 100W4.50 → 5.36fstec_bduRU
Zyxel Communications Corp. USG FLEX 20(W)4.16 → 5.36fstec_bduRU
Zyxel Communications Corp. USG FLEX 2004.50 → 5.36fstec_bduRU
Zyxel Communications Corp. USG FLEX 504.50 → 5.36fstec_bduRU
Zyxel Communications Corp. USG FLEX 50(W)4.16 → 5.36fstec_bduRU
Zyxel Communications Corp. USG FLEX 5004.50 → 5.36fstec_bduRU

showing 20 of 43

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2023-1070Zyxel Firewalls: Mehrere SchwachstellenDeutsch2023-04-24csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Zyxel Firewall ausnutzen, um beliebigen Programmcode auszuführen, Informationen offenzulegen, einen Denial of Service zu verursachen, einen Cross Site Scripting Angriff durchzuführen oder die Konfiguration zu manipulieren.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cert_bund NVD CVE.org MITRE

published 2023-04-24modified 2026-06-17

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references (4)

External citations — patches, advisories, analysis.

scry

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