CVE-2026-4621

Severity: medium (CVSS 5.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-27 · updated 2026-10-26
Weakness: CWE-912

Description

Hidden Functionality vulnerability in NEC Platforms, Ltd. Aterm Series allows a attacker to enable telnet via network.

Affected products

NEC Aterm W1200Ex-Ms Firmware: all versions
NEC Aterm Wf1200Cr Firmware: before 1.6.0 — fixed in 1.6.0
NEC Aterm Wg1200Cr Firmware: before 1.5.0 — fixed in 1.5.0
NEC Aterm Wg1200Hp2 Firmware: all versions
NEC Aterm Wg1200Hp3 Firmware: all versions
NEC Aterm Wg1200Hp4 Firmware: all versions
NEC Aterm Wg1200Hs2 Firmware: all versions
NEC Aterm Wg1200Hs3 Firmware: all versions
NEC Aterm Wg1200Hs4 Firmware: all versions
NEC Aterm Wg1800Hp3 Firmware: all versions
NEC Aterm Wg1800Hp4 Firmware: all versions
NEC Aterm Wg1900Hp2 Firmware: all versions
NEC Aterm Wg1900Hp Firmware: all versions
NEC Aterm Wg2600Hm4 Firmware: before 1.4.2 — fixed in 1.4.2
NEC Aterm Wg2600Hp4 Firmware: before 1.4.2 — fixed in 1.4.2
NEC Aterm Wg2600Hs2 Firmware: before 1.3.2 — fixed in 1.3.2
NEC Corporation Aterm WG2600HS: before 1.7.2 — fixed in 1.7.2
NEC Aterm Wx1500Hp Firmware: before 1.4.2 — fixed in 1.4.2
NEC Aterm Wx3000Hp2 Firmware: before 1.3.2 — fixed in 1.3.2
NEC Aterm Wx3000Hp Firmware: before 2.5.0 — fixed in 2.5.0
NEC Platforms, Ltd. Aterm WX3600HP: through 1.5.3

How to fix

Upgrade to a fixed version: NEC Aterm Wf1200Cr Firmware 1.6.0; NEC Aterm Wg1200Cr Firmware 1.5.0; NEC Aterm Wg2600Hm4 Firmware 1.4.2; NEC Aterm Wg2600Hp4 Firmware 1.4.2; NEC Aterm Wg2600Hs2 Firmware 1.3.2; NEC Corporation Aterm WG2600HS 1.7.2; NEC Aterm Wx1500Hp Firmware 1.4.2; NEC Aterm Wx3000Hp2 Firmware 1.3.2; NEC Aterm Wx3000Hp Firmware 2.5.0. Check the vendor advisory for mitigations.

References

https://jpn.nec.com/security-info/secinfo/nv26-001_en.html

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