Description
A stack buffer overflow exists in the ToToLink A720R Router firmware V4.1.5cu.614_B20230630 within the sysconf binary (sub_401EE0 function). The binary reads the /proc/stat file using fgets() into a local buffer and subsequently parses the line using sscanf() into a single-byte variable with the %s format specifier. Maliciously crafted /proc/stat content can overwrite adjacent stack memory, potentially allowing an attacker with filesystem write privileges to execute arbitrary code on the device.
Affected products
totolink: a720r firmware; totolink: a720r
References2
- github.com/yifan20020708/SGTaint-0-day/blob/main/ToToLink/ToToL… ExploitThird Party Advisory
- www.totolink.net/ Product
Metrics
- CVSS 3.1
-
5.1
MEDIUM
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L - EPSS — exploit probability
- 0% percentile: 15 · as of 11 November 2026
- CWE
- CWE-121
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.