How severe is CVE-2021-21723?

CVE-2021-21723 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-21723 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21723?

CVE-2021-21723 primarily affects Zte Zxr10 9904 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-21723?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-21723 published?

CVE-2021-21723 was published on 2021-01-26 and last updated on 2026-06-17.

CVE-2021-21723

CVE-2021-21723 is a high-severity vulnerability in Zte Zxr10 9904 Firmware with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-401.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 4.3
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-401
Affected product: Zte Zxr10 9904 Firmware
Published: 2021-01-26
Last modified: 2026-06-17

Description

Some ZTE products have a DoS vulnerability. Due to the improper handling of memory release in some specific scenarios, a remote attacker can trigger the vulnerability by performing a series of operations, resulting in memory leak, which may eventually lead to device denial of service. This affects: ZXR10 9904, ZXR10 9908, ZXR10 9916, ZXR10 9904-S, ZXR10 9908-S; all versions up to V1.01.10.B12.

Frequently asked questions

What is CVE-2021-21723?: Some ZTE products have a DoS vulnerability. Due to the improper handling of memory release in some specific scenarios, a remote attacker can trigger the vulnerability by performing a series of operations, resulting in memory leak, which may eventually lead to device denial of service. This affects: ZXR10 9904, ZXR10 9908, ZXR10 9916, ZXR10 9904-S, ZXR10 9908-S; all versions up to V1.01.10.B12.
How severe is CVE-2021-21723?: CVE-2021-21723 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-21723 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21723?: CVE-2021-21723 primarily affects Zte Zxr10 9904 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-21723?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-21723 published?: CVE-2021-21723 was published on 2021-01-26 and last updated on 2026-06-17.

References

http://support.zte.com.cn/support/news/LoopholeInfoDetail.aspx?newsId=1014424

Affected products (5)

cpe:2.3:o:zte:zxr10_9904_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zte:zxr10_9908_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zte:zxr10_9916_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zte:zxr10_9904-s_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:zte:zxr10_9908-s_firmware:*:*:*:*:*:*:*:*

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