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CVE-2023-28767

HIGH
8.8
CVSS Score
Published: July 17, 2023 at 04:59 PM UTC
Updated: June 17, 2026 at 05:48 AM UTC
46 products affected across 1 vendorUsg Flex 100W FirmwareUSG FLEX 200 firmwareUSG FLEX 700 firmware

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Severity
HIGH8.8
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

The configuration parser fails to sanitize user-controlled input in the Zyxel ATP series firmware versions 5.10 through 5.36, USG FLEX series firmware versions 5.00 through 5.36,  USG FLEX 50(W) series firmware versions 5.10 through 5.36, USG20(W)-VPN series firmware versions 5.10 through 5.36, and VPN series firmware versions 5.00 through 5.36. An unauthenticated, LAN-based attacker could leverage the vulnerability to inject some operating system (OS) commands into the device configuration data on an affected device when the cloud management mode is enabled.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Usg 20W VPN Firmware· Zyxel
95%
5.10 ≤ v < 5.37
Affected range stops below 5.37, so it looks safe — our inference, not a vendor statement
Usg 2200-vpn Firmware· Zyxel
95%
5.00 ≤ v < 5.37
Affected range stops below 5.37, so it looks safe — our inference, not a vendor statement
zyxel-usg-2200-vpn (same device)
Usg Flex 100 Firmware· Zyxel
95%
5.00 ≤ v < 5.37
Affected range stops below 5.37, so it looks safe — our inference, not a vendor statement
zyxel-usg-flex-100 (same device)
Usg Flex 100W Firmware· Zyxel
95%
5.00 ≤ v < 5.37
Affected range stops below 5.37, so it looks safe — our inference, not a vendor statement
zyxel-usg-flex-100w (same device)
USG FLEX 200 firmware· Zyxel
95%
5.00 ≤ v < 5.37
Affected range stops below 5.37, so it looks safe — our inference, not a vendor statement
zyxel-usg-flex-200 (same device)
Usg Flex 50 Firmware· Zyxel
95%
5.00 ≤ v < 5.37
Affected range stops below 5.37, so it looks safe — our inference, not a vendor statement
zyxel-usg-flex-50 (same device)
USG FLEX 500 firmware· Zyxel
95%
5.00 ≤ v < 5.37
Affected range stops below 5.37, so it looks safe — our inference, not a vendor statement
zyxel-usg-flex-500 (same device)
Usg Flex 50W Firmware· Zyxel
95%
5.00 ≤ v < 5.37
Affected range stops below 5.37, so it looks safe — our inference, not a vendor statement
USG FLEX 700 firmware· Zyxel
95%
5.00 ≤ v < 5.37
Affected range stops below 5.37, so it looks safe — our inference, not a vendor statement
zyxel-usg-flex-700 (same device)
Zywall ATP100 Firmware· Zyxel
95%
5.10 ≤ v < 5.37
Affected range stops below 5.37, so it looks safe — our inference, not a vendor statement
zyxel-zywall-atp100 (same device)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (1)

Vendor Advisory
Source: [email protected]
https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-wlan-controllers

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHZyxel
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-78

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