Cross-site scripting in Zyxel GS1900-8 Firmware
Priority LOW 20CWE-79Published · Updated
Key facts
- Attack vector
- Adjacent network
- Privileges required
- High
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-79.
Summary
A vulnerability was found in the CGI program in Zyxel GS1900-8 firmware version V2.60, that did not properly sterilize packet contents and could allow an authenticated, local user to perform a cross-site scripting (XSS) attack via a crafted LLDP packet.
Why it matters now
EPSS 0.00268 19th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Zyxel | GS1900-8 Firmware | 2.60 | — | No fix listed | CNA |
- GS1900-8 Firmware VendorZyxel Affected 2.60 Fixed in — No fix listed CNA
CPE configurations NVD · 24
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:zyxel:gs1900-8_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-8:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:gs1900-8hp_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-8hp:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:gs1900-10hp_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-10hp:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:gs1900-16_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-16:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:gs1900-24e_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-24e:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
- cpe:2.3:o:zyxel:gs1900-8_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-8:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:gs1900-8hp_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-8hp:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:gs1900-10hp_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-10hp:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:gs1900-16_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-16:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:gs1900-24e_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-24e:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
Show 14 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:zyxel:gs1900-24ep_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-24ep:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:gs1900-24_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-24:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:gs1900-24hp_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-24hp:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:gs1900-24hpv2_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-24hpv2:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:gs1900-48_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-48:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:gs1900-48hp_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-48hp:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
| cpe:2.3:o:zyxel:gs1900-48hpv2_firmware:*:*:*:*:*:*:*:* | before 2.70 | Vulnerable | Zyxel |
| cpe:2.3:h:zyxel:gs1900-48hpv2:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Zyxel |
- cpe:2.3:o:zyxel:gs1900-24ep_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-24ep:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:gs1900-24_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-24:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:gs1900-24hp_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-24hp:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:gs1900-24hpv2_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-24hpv2:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:gs1900-48_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-48:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:gs1900-48hp_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-48hp:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Zyxel
- cpe:2.3:o:zyxel:gs1900-48hpv2_firmware:*:*:*:*:*:*:*:* Versions before 2.70 Vulnerable ·Zyxel
- cpe:2.3:h:zyxel:gs1900-48hpv2:-:*:*:*:*:*:*:* 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-2021-35030
- 2026-10-03 Alias added: GHSA-g78g-pgq7-f6cr
References
More Zyxel Gs1900-10hp Firmware vulnerabilities
- TI-2026-06387 Stack-based buffer overflow in Zyxel GS1900-48HPv2 firmware KEVCVSS 3.1HIGH 8.8
- TI-2019-11869 An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. CVSS 3.1CRITICAL 9.8
- TI-2016-01221 Cisco NX-OS 6.0(2)U6(1) through 6.0(2)U6(5) on Nexus 3000 devices and 6.0(2)A6(1) through… CVSS 3.0CRITICAL 9.8
- TI-2015-05062 Belkin F9K1102 2 devices with firmware 2.10.17 rely on client-side JavaScript code for… CVSS 3.0CRITICAL 9.8
- TI-2015-05061 The web management interface on Belkin F9K1102 2 devices with firmware 2.10.17 has a… CVSS 3.0CRITICAL 9.8
- TI-2019-11872 An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. CVSS 3.1CRITICAL 9.1
Sources
- CVE-2021-35030 · CVE Program
- CVE-2021-35030 · NVD
- FIRST EPSS
- GHSA-g78g-pgq7-f6cr · 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