CVE-2018-5721Stack-based buffer overflow in the ej_update_variables function in router/httpd/web.c on ASUS routers (when using software from…
- 8.8HighCVSS base score
- 1.9%Exploitation in 30 daysEPSS · top 20% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By mitre
- 1 day later
· 1 day later
Published
- 7 years later
· 7 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | High8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 1.9% · top 20% of all CVEs (12 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.
Affected products
n/a
- affected n/a
References
References1
- http://www.w0lfzhang.com/2018/01/17/ASUS-router-stack-overflow-in-http-server/ (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2018-17490 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2018-5721)Record last updated .