CVE-2025-60685: totolink a720r_firmware Stack-based Buffer Overflow

Vulnerability summary

CVE-2025-60685 is a medium (CVSS 5.1) Stack-based Buffer Overflow vulnerability in totolink a720r_firmware. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 13-11-2025
   PublishedVulnerability first disclosed.
2. 05-07-2026
   Last modifiedVulnerability information updated.

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.

• CWE-121Stack-based Buffer OverflowA stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).