CVE-2023-6399
A format string vulnerability in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2023-6399- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-134
- Updated
- 2026-11-02
EUVDEUVD-2023-58636
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.
- Record
EUVD-2023-58636- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-6mfv-h538-gwvr
A format string vulnerability in Zyxel ATP series firmware versions from 4.32 through 5.37 Patch...
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, and USG20(W)-VPN series firmware versions from 4.16 through 5.37 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.
- Record
GHSA-6mfv-h538-gwvr- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-134
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2023-6399- CVSS 3.1
- 5.7 Medium
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-134
- Updated
- 2026-11-02
Affected products
- zyxel atp series firmware
- zyxel usg flex 50(w) series firmware
- zyxel usg flex h series firmware
- zyxel usg flex series firmware
- zyxel usg20(w)-vpn series firmware
- zyxel atp100 firmware
- zyxel atp100w firmware
- zyxel atp200 firmware
- zyxel atp500 firmware
- zyxel atp700 firmware
- zyxel atp800 firmware
- zyxel uos
Show 15 moreShow less
- zyxel usg20-vpn firmware
- zyxel usg20w-vpn firmware
- zyxel usg flex 100 firmware
- zyxel usg flex 100ax firmware
- zyxel usg flex 100h firmware
- zyxel usg flex 100w firmware
- zyxel usg flex 200 firmware
- zyxel usg flex 200h firmware
- zyxel usg flex 200hp firmware
- zyxel usg flex 500 firmware
- zyxel usg flex 500h firmware
- zyxel usg flex 50 firmware
- zyxel usg flex 50w firmware
- zyxel usg flex 700 firmware
- zyxel usg flex 700h firmware
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-6399 is a medium vulnerability (CVSS 5.7) in Zyxel Atp Series Firmware, published February 20, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.65%, the 51st percentile. No source names a fixed version.