What is CVE-2026-31027?

CVE-2026-31027 is a critical-severity vulnerability in Totolink A3600r, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2026-04-01.

How severe is CVE-2026-31027?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Totolink A3600r

CVE-2026-31027

TOTOlink A3600R v5.9c.4959 contains a buffer overflow vulnerability in the setAppEasyWizardConfig interface of /lib/cste_modules/app.so. The vulnerability occurs because the rootSsid parameter is not properly validated for length, allowing remote attackers to trigger a buffer overflow, potentially leading to arbitrary code execution or denial of service.

Vulnerability class: Buffer Overflow

Published 2026-04-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.016 (74.6th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 74.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.016 · change: +0.010

Affected products

Totolink A3600r
Totolink A3600r Firmware — versions 5.9c.4959

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

github.com/SunnyYANGyaya/cuicuishark-sheep-fishIOT/blob/main/ToTolink/A3600R/ro… (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2026-31027?: CVE-2026-31027 is a critical-severity vulnerability in Totolink A3600r, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2026-04-01.
How severe is CVE-2026-31027?: Critical severity. CVSS v3 base score is 9.8 out of 10.