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Fencer Vulns
medium 4.6

CVE-2021-21739 json

A ZTE's product of the transport network access layer has a security vulnerability.

published 2021-08-05 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-8911

cvss
4.6
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

A ZTE's product of the transport network access layer has a security vulnerability. Because the system does not sufficiently verify the data reliability, attackers could replace an authenticated optical module on the equipment with an unauthenticated one, bypassing system authentication and detection, thus affecting signal transmission. This affects: <ZXCTN 6120H><V5.10.00B24>

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 4.6 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:N/I:P/A:N

Affected products

  • n/a <ZXCTN 6120H>

Classification

Weakness
  • CWE-345 Insufficient Verification of Data Authenticity

References

Sources

Fencer Vulns 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.