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Fencer Intel
high 7.5

CVE-2021-3166 json

An issue was discovered on ASUS DSL-N14U-B1 1.1.2.3_805 devices.

published 5y ago modified 4mo ago also EUVD-2021-26509

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.9%
EPSS 2.9% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

An issue was discovered on ASUS DSL-N14U-B1 1.1.2.3_805 devices. An attacker can upload arbitrary file content as a firmware update when the filename Settings_DSL-N14U-B1.trx is used. Once this file is loaded, shutdown measures on a wide range of services are triggered as if it were a real update, resulting in a persistent outage of those services.

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Exploit prediction

2.88% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • kaisersource.github.io https://kaisersource.github.io/dsl-n14u referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/kaisersource/kaisersource.github.io/blob/main/_posts/2021-01-17-dsl-n14u.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.