CVE-2023-33009

criticalpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.281 · 98 %ileDEEURUUS

grimoire priorityP0 · Act now

Exploitable?

Yes · in the wild

CISA KEV

Likely / severe?

28.1% (98th) EPSS

CVSS 9.8 · critical

Is it mine?

59 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

added 2023-06-05remediate by 2023-06-26

required action Apply updates per vendor instructions.

EPSS · scored 2026-10-24

Zyxel Multiple Firewalls Buffer Overflow Vulnerability

A buffer overflow vulnerability in the notification function in Zyxel ATP series firmware versions 4.60 through 5.36 Patch 1, USG FLEX series firmware versions 4.60 through 5.36 Patch 1, USG FLEX 50(W) firmware versions 4.60 through 5.36 Patch 1, USG20(W)-VPN firmware versions 4.60 through 5.36 Patch 1, VPN series firmware versions 4.60 through 5.36 Patch 1, ZyWALL/USG series firmware versions 4.60 through 4.73 Patch 1, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device.

cvss

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

9.8

010

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

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.19.8criticalAV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · security@zyxel.com.twexploitability 3.9 · impact 5.9

ssvc

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

Exploitation: active · Automatable: yes · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-120USprimaryCWE-120US

affected products (59)

Products and version ranges known to be affected.

Zyxel ATP series firmware≤ 4.60 through 5.36 Patch 1enisa_euvdEU
Zyxel USG FLEX 50(W) firmware≤ 4.60 through 5.36 Patch 1enisa_euvdEU
Zyxel USG FLEX series firmware≤ 4.60 through 5.36 Patch 1enisa_euvdEU
Zyxel USG20(W)-VPN firmware≤ 4.60 through 5.36 Patch 1enisa_euvdEU
Zyxel VPN series Firmware≤ 4.60 through 5.36 Patch 1enisa_euvdEU
Zyxel ZyWALL/USG series firmware≤ 4.60 through 4.73 Patch 1enisa_euvdEU
Zyxel Communications Corp. ATP4.32 → 5.36 Patch 1fstec_bduRU
Zyxel Communications Corp. USG4.25 → 4.73 Patch 1fstec_bduRU
Zyxel Communications Corp. USG FLEX4.50 → 5.36 Patch 1fstec_bduRU
Zyxel Communications Corp. USG FLEX 50(W)4.25 → 5.36 Patch 1fstec_bduRU
Zyxel Communications Corp. USG USG20(W)-VPN4.25 → 5.36 Patch 1fstec_bduRU
Zyxel Communications Corp. VPN4.30 → 5.36 Patch 1fstec_bduRU
Zyxel Communications Corp. ZyWALL4.25 → 4.73 Patch 1fstec_bduRU
zyxel atp100 firmware4.60 → 5.36nvdUScpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
zyxel atp100 firmware= 5.36nvdUScpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
zyxel atp100w firmware4.60 → 5.36nvdUScpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
zyxel atp100w firmware= 5.36nvdUScpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
zyxel atp200 firmware4.60 → 5.36nvdUScpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
zyxel atp200 firmware= 5.36nvdUScpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
zyxel atp500 firmware4.60 → 5.36nvdUScpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*

showing 20 of 59

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2023-1299Zyxel Firewalls: Mehrere SchwachstellenDeutsch2023-05-24csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Zyxel Firewalls ausnutzen, um beliebigen Programmcode auszuführen oder einen Denial of Service zu verursachen.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu nvd cert_bund NVD CVE.org MITRE

published 2023-05-24modified 2026-06-17

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Related entries.

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+5656 more

references (6)

External citations — patches, advisories, analysis.

scry

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