What is CVE-2021-42887?

CVE-2021-42887 is a critical-severity vulnerability in Totolink Ex1200t. CVSS score: 9.8/10. Published 2022-06-03.

How severe is CVE-2021-42887?

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

Is CVE-2021-42887 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Totolink Ex1200t

CVE-2021-42887

In TOTOLINK EX1200T V4.1.2cu.5215, an attacker can bypass login by sending a specific request through formLoginAuth.htm.

Published 2022-06-03 · 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: 0.443 (98.7th percentile), scored 2026-09-30.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 99th percentile — 98.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.443 · newest: 0.443 · change: 0.000

Affected products

Totolink Ex1200t
Totolink Ex1200t Firmware — versions 4.1.2cu.5215

Public proof-of-concept exploits

References

github.com/p1Kk/vuln/blob/main/totolink_ex1200t_login_bypass.md (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-42887?: CVE-2021-42887 is a critical-severity vulnerability in Totolink Ex1200t. CVSS score: 9.8/10. Published 2022-06-03.
How severe is CVE-2021-42887?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-42887 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.