CVE-2019-9955
On Zyxel ATP200, ATP500, ATP800, USG20-VPN, USG20W-VPN, USG40, USG40W, USG60, USG60W, USG110, USG210, USG310, USG1100, USG1900, USG2200-VPN, ZyWALL 110, ZyWALL 310, ZyWALL 1100 devices, the security firewall login page is vulnerable to Reflected XSS via…
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 21.2%, higher than 98% of all known CVEs. Patch or mitigate before the next change window.
Description
On Zyxel ATP200, ATP500, ATP800, USG20-VPN, USG20W-VPN, USG40, USG40W, USG60, USG60W, USG110, USG210, USG310, USG1100, USG1900, USG2200-VPN, ZyWALL 110, ZyWALL 310, ZyWALL 1100 devices, the security firewall login page is vulnerable to Reflected XSS via the unsanitized 'mp_idx' parameter.
- CVSS 3.0
- 6.1 MEDIUMCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- EPSS
- 21.18% probability · 98th percentile
- Public exploits
- 1 in Exploit-DB · first 16 April 2019
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Affected
- zyxel/atp200 firmware · zyxel/atp500 firmware · zyxel/atp800 firmware · zyxel/usg20-vpn firmware · zyxel/usg20w-vpn firmware · zyxel/usg40 firmware · zyxel/usg40w firmware · zyxel/usg60 firmware · zyxel/usg60w firmware · zyxel/usg110 firmware · zyxel/usg210 firmware · zyxel/usg310 firmware · zyxel/usg1100 firmware · zyxel/usg1900 firmware · zyxel/usg2200-vpn firmware · zyxel/zywall 110 firmware · zyxel/zywall 310 firmware · zyxel/zywall 1100 firmware · zyxel/vpn50 firmware · zyxel/vpn100 firmware · +1 more
- Source
- cve@mitre.org
EPSS moved from 18.6% on 21 September 2026 to 21.2% on 26 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
Public exploits (1)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
References
- http://packetstormsecurity.com/files/152525/Zyxel-ZyWall-Cross-Site-Scripting.htmlExploit, Third Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2019/Apr/22Mailing List, Third Party Advisory
- https://www.exploit-db.com/exploits/46706/Exploit, Third Party Advisory, VDB Entry
- https://www.securitymetrics.com/blog/Zyxel-Devices-Vulnerable-Cross-Site-Scripting-Login-pagePatch, Third Party Advisory
- https://www.zyxel.com/support/reflected-cross-site-scripting-vulnerability-of-firewalls.shtmlVendor Advisory
- http://packetstormsecurity.com/files/152525/Zyxel-ZyWall-Cross-Site-Scripting.htmlExploit, Third Party Advisory, VDB Entry
- http://seclists.org/fulldisclosure/2019/Apr/22Mailing List, Third Party Advisory
- https://www.exploit-db.com/exploits/46706/Exploit, Third Party Advisory, VDB Entry
- https://www.securitymetrics.com/blog/Zyxel-Devices-Vulnerable-Cross-Site-Scripting-Login-pagePatch, Third Party Advisory
- https://www.zyxel.com/support/reflected-cross-site-scripting-vulnerability-of-firewalls.shtmlVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.