Buffer overflow in Zyxel ATP series firmware
Priority LOW 29CWE-120Published · Updated
Key facts
- Attack vector
- Adjacent network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-120 and the CVSS impact.
Summary
A buffer overflow vulnerability in the Zyxel ATP series firmware versions 4.32 through 5.36 Patch 2, USG FLEX series firmware versions 4.50 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 4.16 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 4.16 through 5.36 Patch 2, VPN series firmware versions 4.30 through 5.36 Patch 2, NXC2500 firmware versions 6.10(AAIG.0) through 6.10(AAIG.3), and NXC5500 firmware versions 6.10(AAOS.0) through 6.10(AAOS.4), could allow an unauthenticated, LAN-based attacker to cause denial of service (DoS) conditions by sending a crafted request to the CAPWAP daemon.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.003 22nd 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
- Partial
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 | 4.32 through 5.36 Patch 2 | — | No fix listed | CNA |
| Zyxel | USG FLEX series firmware | 4.50 through 5.36 Patch 2 | — | No fix listed | CNA |
| Zyxel | USG FLEX 50(W) series firmware | 4.16 through 5.36 Patch 2 | — | No fix listed | CNA |
| Zyxel | USG20(W)-VPN series firmware | 4.16 through 5.36 Patch 2 | — | No fix listed | CNA |
| Zyxel | VPN series firmware | 4.30 through 5.36 Patch 2 | — | No fix listed | CNA |
| Zyxel | NXC2500 firmware | 6.10(AAIG.0) through 6.10(AAIG.3) | — | No fix listed | CNA |
| Zyxel | NXC5500 firmware | 6.10(AAOS.0) through 6.10(AAOS.4) | — | No fix listed | CNA |
- ATP series firmware VendorZyxel Affected 4.32 through 5.36 Patch 2 Fixed in — No fix listed CNA
- USG FLEX series firmware VendorZyxel Affected 4.50 through 5.36 Patch 2 Fixed in — No fix listed CNA
- USG FLEX 50(W) series firmware VendorZyxel Affected 4.16 through 5.36 Patch 2 Fixed in — No fix listed CNA
- USG20(W)-VPN series firmware VendorZyxel Affected 4.16 through 5.36 Patch 2 Fixed in — No fix listed CNA
- VPN series firmware VendorZyxel Affected 4.30 through 5.36 Patch 2 Fixed in — No fix listed CNA
- NXC2500 firmware VendorZyxel Affected 6.10(AAIG.0) through 6.10(AAIG.3) Fixed in — No fix listed CNA
- NXC5500 firmware VendorZyxel Affected 6.10(AAOS.0) through 6.10(AAOS.4) Fixed in — No fix listed CNA
CPE configurations NVD · 48
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:zyxel:usg_20w-vpn_firmware:*:*:*:*:*:*:*:* | 4.16 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:usg_2200-vpn_firmware:*:*:*:*:*:*:*:* | 4.30 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:*:*:*:*:*:*:*:* | 4.50 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:*:*:*:*:*:*:*:* | 4.50 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:*:*:*:*:*:*:*:* | 4.50 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_20w-vpn_firmware:*:*:*:*:*:*:*:* Versions 4.16 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:usg_2200-vpn_firmware:*:*:*:*:*:*:*:* Versions 4.30 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 4.50 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 4.50 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 4.50 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_flex_200:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
Show 38 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:zyxel:usg_flex_50_firmware:*:*:*:*:*:*:*:* | 4.50 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_flex_500_firmware:*:*:*:*:*:*:*:* | 4.50 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:*:*:*:*:*:*:*:* | 4.50 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:*:*:*:*:*:*:*:* | 4.50 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_atp100_firmware:*:*:*:*:*:*:*:* | 4.32 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:*:*:*:*:*:*:*:* | 4.32 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:*:*:*:*:*:*:*:* | 4.32 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:*:*:*:*:*:*:*:* | 4.32 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:*:*:*:*:*:*:*:* | 4.32 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:*:*:*:*:*:*:*:* | 4.32 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:zywall_vpn100_firmware:*:*:*:*:*:*:*:* | 4.30 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:*:*:*:*:*:*:*:* | 4.30 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:*:*:*:*:*:*:*:* | 4.30 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:*:*:*:*:*:*:*:* | 4.30 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:*:*:*:*:*:*:*:* | 4.30 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:*:*:*:*:*:*:*:* | 4.30 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:*:*:*:*:*:*:*:* | 4.30 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:nxc2500_firmware:*:*:*:*:*:*:*:* | 6.10\(aaig.0\) – 6.10\(aaig.3\) | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:nxc2500:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:nxc5500_firmware:*:*:*:*:*:*:*:* | 6.10\(aaos.0\) – 6.10\(aaos.4\) | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:nxc5500:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
- cpe:2.3:o:zyxel:usg_flex_50_firmware:*:*:*:*:*:*:*:* Versions 4.50 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:usg_flex_50:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:usg_flex_500_firmware:*:*:*:*:*:*:*:* Versions 4.50 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 4.50 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 4.50 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_atp100_firmware:*:*:*:*:*:*:*:* Versions 4.32 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 4.32 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 4.32 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 4.32 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 4.32 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 4.32 to before 5.37 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:zywall_atp800:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:zywall_vpn100_firmware:*:*:*:*:*:*:*:* Versions 4.30 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 4.30 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 4.30 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 4.30 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 4.30 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 4.30 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 4.30 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:nxc2500_firmware:*:*:*:*:*:*:*:* Versions 6.10\(aaig.0\) – 6.10\(aaig.3\) Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:nxc2500:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:nxc5500_firmware:*:*:*:*:*:*:*:* Versions 6.10\(aaos.0\) – 6.10\(aaos.4\) Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:nxc5500:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
Remediation
No fixed version listed by the sources yet.
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
Zyxel ATP series firmware, NXC2500 firmware and 5 more products — zyxel.com/global/en/support/security-advisories/zyxel-secur…
5 records Highest priority Priority MEDIUM 2 MEDIUM, 3 LOW
Other records, highest priority first
- TI-2023-16983 OS command injection in Zyxel USG FLEX series firmwarePriority MEDIUM 41
- TI-2023-13277 OS command injection in Zyxel ATP series firmwarePriority MEDIUM 40
- TI-2023-16985 OS command injection in Zyxel ATP series firmwarePriority LOW 38
Timeline
- 2026-10-02 Threatist record created from CVE-2023-34140
- 2026-10-03 Alias added: GHSA-65px-649g-rj37
References
More Zyxel Nxc2500 Firmware vulnerabilities
- 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
- TI-2023-16985 OS command injection in Zyxel ATP series firmware CVSS 3.1HIGH 8.0
Sources
- CVE-2023-34140 · CVE Program
- CVE-2023-34140 · NVD
- FIRST EPSS
- GHSA-65px-649g-rj37 · 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