CVE-2018-5721
Stack-based buffer overflow in the ej_update_variables function in router/httpd/web.c on ASUS routers (when using software from https://github.com/RMerl/asuswrt-merlin) allows web authenticated attackers to execute code via a request that updates a…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.94%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Stack-based buffer overflow in the ej_update_variables function in router/httpd/web.c on ASUS routers (when using software from https://github.com/RMerl/asuswrt-merlin) allows web authenticated attackers to execute code via a request that updates a setting. In ej_update_variables, the length of the variable action_script is not checked, as long as it includes a "_wan_if" substring.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.94% probability · 80th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- asuswrt-merlin/asuswrt-merlin
- Source
- cve@mitre.org
EPSS 1.9% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.w0lfzhang.com/2018/01/17/ASUS-router-stack-overflow-in-http-server/Exploit, Third Party Advisory
- http://www.w0lfzhang.com/2018/01/17/ASUS-router-stack-overflow-in-http-server/Exploit, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.