CVE-2021-21723Network attack vector

Service interruption via remotely triggered memory leak

Published Jan 21, 2021 · Updated Aug 3, 2024

Memory leak in ZTE ZXR10 9904, 9908, 9916, 9904-S, and 9908-S through 1.01.10.B12 allows remote attackers to interrupt service. The affected firmware fails to release memory after a series of unspecified remote operations, progressively exhausting device memory. No authentication or user interaction is required; the documented consequence is device denial of service, with no reported confidentiality or integrity impact.

CVSS severity8.6
High
EPSS probability1.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in ZTE ZXR10 9904, 9908, 9916, 9904-S, and 9908-S through 1.01.10.B12 allows remote attackers to interrupt service. The affected firmware fails to release memory after a series of unspecified remote operations, progressively exhausting device memory. No authentication or user interaction is required; the documented consequence is device denial of service, with no reported confidentiality or integrity impact.

The record

CVE
CVE-2021-21723
Published
Jan 21, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-401, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
8.6ZTE CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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