A format string vulnerability in the Zyxel ATP series firmware versions 5.10 through 5.36…
Priority MEDIUM 40CWE-134Published · Updated
Key facts
- Attack vector
- Adjacent network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-134 and the CVSS impact.
Summary
A format string vulnerability in the Zyxel ATP series firmware versions 5.10 through 5.36 Patch 2, USG FLEX series firmware versions 5.00 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 5.10 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 5.10 through 5.36 Patch 2, and VPN series firmware versions 5.00 through 5.36 Patch 2, could allow an unauthenticated, LAN-based attacker to execute some OS commands by using a crafted PPPoE configuration on an affected device when the cloud management mode is enabled.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0034 27th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Zyxel | ATP series firmware | 5.10 through 5.36 Patch 2 | — | No fix listed | CNA |
| Zyxel | USG FLEX series firmware | 5.00 through 5.36 Patch 2 | — | No fix listed | CNA |
| Zyxel | USG FLEX 50(W) series firmware | 5.10 through 5.36 Patch 2 | — | No fix listed | CNA |
| Zyxel | USG20(W)-VPN series firmware | 5.10 through 5.36 Patch 2 | — | No fix listed | CNA |
| Zyxel | VPN series firmware | 5.00 through 5.36 Patch 2 | — | No fix listed | CNA |
- ATP series firmware VendorZyxel Affected 5.10 through 5.36 Patch 2 Fixed in — No fix listed CNA
- USG FLEX series firmware VendorZyxel Affected 5.00 through 5.36 Patch 2 Fixed in — No fix listed CNA
- USG FLEX 50(W) series firmware VendorZyxel Affected 5.10 through 5.36 Patch 2 Fixed in — No fix listed CNA
- USG20(W)-VPN series firmware VendorZyxel Affected 5.10 through 5.36 Patch 2 Fixed in — No fix listed CNA
- VPN series firmware VendorZyxel Affected 5.00 through 5.36 Patch 2 Fixed in — No fix listed CNA
CPE configurations NVD · 44
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:zyxel:usg_2200-vpn_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:usg_2200-vpn:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:usg_flex_100_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:usg_flex_100:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:usg_flex_100w_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:usg_flex_100w:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:usg_flex_200_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:usg_flex_200:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:usg_flex_50_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:usg_flex_50:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
- cpe:2.3:o:zyxel:usg_2200-vpn_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_2200-vpn:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:usg_flex_100_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_flex_100:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:usg_flex_100w_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_flex_100w:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:usg_flex_200_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_flex_200:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:usg_flex_50_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_flex_50:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
Show 34 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:zyxel:usg_flex_500_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:usg_flex_500:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:usg_flex_50w_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:usg_flex_50w:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:usg_flex_700_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:usg_flex_700:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_vpn100_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_vpn100:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_vpn2s_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_vpn2s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_vpn300_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_vpn300:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_vpn50_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_vpn50:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_vpn_100_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_vpn_100:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_vpn_300_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_vpn_300:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_vpn_50_firmware:*:*:*:*:*:*:*:* | 5.00 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_vpn_50:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:usg_20w-vpn_firmware:*:*:*:*:*:*:*:* | 5.10 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:usg_20w-vpn:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_atp100_firmware:*:*:*:*:*:*:*:* | 5.10 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_atp100:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_atp100w_firmware:*:*:*:*:*:*:*:* | 5.10 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_atp100w:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_atp200_firmware:*:*:*:*:*:*:*:* | 5.10 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_atp200:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_atp500_firmware:*:*:*:*:*:*:*:* | 5.10 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_atp500:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_atp700_firmware:*:*:*:*:*:*:*:* | 5.10 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_atp700:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:zywall_atp800_firmware:*:*:*:*:*:*:*:* | 5.10 to before 5.37 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:zywall_atp800:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
- cpe:2.3:o:zyxel:usg_flex_500_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_flex_500:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:usg_flex_50w_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_flex_50w:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:usg_flex_700_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_flex_700:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_vpn100_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_vpn100:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_vpn2s_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_vpn2s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_vpn300_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_vpn300:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_vpn50_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_vpn50:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_vpn_100_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_vpn_100:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_vpn_300_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_vpn_300:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_vpn_50_firmware:*:*:*:*:*:*:*:* Versions 5.00 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_vpn_50:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:usg_20w-vpn_firmware:*:*:*:*:*:*:*:* Versions 5.10 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_20w-vpn:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_atp100_firmware:*:*:*:*:*:*:*:* Versions 5.10 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_atp100:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_atp100w_firmware:*:*:*:*:*:*:*:* Versions 5.10 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_atp100w:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_atp200_firmware:*:*:*:*:*:*:*:* Versions 5.10 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_atp200:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_atp500_firmware:*:*:*:*:*:*:*:* Versions 5.10 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_atp500:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_atp700_firmware:*:*:*:*:*:*:*:* Versions 5.10 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_atp700:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_atp800_firmware:*:*:*:*:*:*:*:* Versions 5.10 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_atp800:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2023-33011
- 2026-10-03 Alias added: GHSA-cf8h-9592-vmxr
References
More Zyxel Usg 20w-vpn Firmware vulnerabilities
- TI-2023-16198 Buffer overflow in Zyxel ATP series firmware KEVCVSS 3.1CRITICAL 9.8
- TI-2023-16197 Buffer overflow in Zyxel ATP series firmware KEVCVSS 3.1CRITICAL 9.8
- TI-2023-16200 OS command injection in Zyxel ATP series firmware CVSS 3.1HIGH 8.8
- TI-2023-12581 OS command injection in Zyxel ATP series firmware CVSS 3.1HIGH 8.8
- TI-2022-09869 Improper input validation in Zyxel USG/ZyWALL series firmware CVSS 3.1HIGH 7.8
- TI-2022-09870 OS command injection in Zyxel USG/ZyWALL series firmware CVSS 3.1HIGH 7.8
Sources
- CVE-2023-33011 · CVE Program
- CVE-2023-33011 · NVD
- FIRST EPSS
- GHSA-cf8h-9592-vmxr · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences