CVE-2023-6399

mediumpriority · track · 26EPSS 0.006 · 51 %ileDEEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

0.65% (51st) EPSS

CVSS 6.5 · medium

Is it mine?

53 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

EPSS · scored 2026-10-27

A format string vulnerability 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, and USG FLEX H series firmware versions from 1.10 through 1.10 Patch 1 could allow an authenticated IPSec VPN user to cause DoS conditions against the “deviceid” daemon by sending a crafted hostname to an affected device if it has the “Device Insight” feature enabled.

cvss

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

6.5

010

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

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 2.8 · impact 3.6

v3.15.7mediumAV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU

v3.15.7mediumCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU

v3.15.7mediumCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · security@zyxel.com.twexploitability 2.1 · impact 3.6

v3.16mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

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

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-134USCWE-134US

affected products (53)

Products and version ranges known to be affected.

Zyxel ATP series firmware≤ version 4.32 through 5.37 Patch 1enisa_euvdEU
Zyxel USG FLEX 50(W) series firmware≤ version 4.16 through 5.37 Patch 1enisa_euvdEU
Zyxel USG FLEX H series firmware≤ version 1.10 through 1.10 Patch 1enisa_euvdEU
Zyxel USG FLEX series firmware≤ version 4.50 through 5.37 Patch 1enisa_euvdEU
Zyxel USG20(W)-VPN series firmware≤ version 4.16 through 5.37 Patch 1enisa_euvdEU
Zyxel Communications Corp. ATP5.10 → 5.37 Patch 1fstec_bduRU
Zyxel Communications Corp. USG 20(W)-VPN5.10 → 5.37 Patch 1fstec_bduRU
Zyxel Communications Corp. USG FLEX5.10 → 5.37 Patch 1fstec_bduRU
Zyxel Communications Corp. USG FLEX 50(W)5.10 → 5.37 Patch 1fstec_bduRU
Zyxel Communications Corp. USG FLEX H1.10 → 1.10 Patch 1fstec_bduRU
zyxel atp100 firmware5.10 → 5.37nvdUScpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
zyxel atp100 firmware= 5.37nvdUScpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
zyxel atp100w firmware5.10 → 5.37nvdUScpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
zyxel atp100w firmware= 5.37nvdUScpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
zyxel atp200 firmware5.10 → 5.37nvdUScpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
zyxel atp200 firmware= 5.37nvdUScpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
zyxel atp500 firmware5.10 → 5.37nvdUScpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*
zyxel atp500 firmware= 5.37nvdUScpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*
zyxel atp700 firmware5.10 → 5.37nvdUScpe:2.3:o:zyxel:atp700_firmware:*:*:*:*:*:*:*:*
zyxel atp700 firmware= 5.37nvdUScpe:2.3:o:zyxel:atp700_firmware:*:*:*:*:*:*:*:*

showing 20 of 53

advisories (1)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2024-0421Zyxel Firewall: Mehrere SchwachstellenDeutsch2024-02-19csaf · cert_bundDE
Ein entfernter Angreifer kann mehrere Schwachstellen in Zyxel Firewall ausnutzen, um einen Denial-of-Service-Zustand zu erzeugen oder beliebigen Code auszuführen.

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 2024-02-20modified 2026-06-17

references (4)

External citations — patches, advisories, analysis.

scry

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