How severe is CVE-2021-21743?

CVE-2021-21743 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2021-21743 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21743?

CVE-2021-21743 primarily affects Zte Mf971r 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-2021-21743?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-21743 published?

CVE-2021-21743 was published on 2021-10-20 and last updated on 2026-06-17.

CVE-2021-21743

CVE-2021-21743 is a medium-severity vulnerability in Zte Mf971r Firmware with a CVSS 3.x base score of 4.3. 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-74.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.3
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-74
Affected product: Zte Mf971r Firmware
Published: 2021-10-20
Last modified: 2026-06-17

Description

ZTE MF971R product has a CRLF injection vulnerability. An attacker could exploit the vulnerability to modify the HTTP response header information through a specially crafted HTTP request.

Frequently asked questions

What is CVE-2021-21743?: ZTE MF971R product has a CRLF injection vulnerability. An attacker could exploit the vulnerability to modify the HTTP response header information through a specially crafted HTTP request.
How severe is CVE-2021-21743?: CVE-2021-21743 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2021-21743 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21743?: CVE-2021-21743 primarily affects Zte Mf971r 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-2021-21743?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-21743 published?: CVE-2021-21743 was published on 2021-10-20 and last updated on 2026-06-17.

References

https://support.zte.com.cn/support/news/LoopholeInfoDetail.aspx?newsId=1019764

Affected products (5)

cpe:2.3:o:zte:mf971r_firmware:v1.0.0b05:*:*:*:*:*:*:*
cpe:2.3:o:zte:mf971r_firmware:1v1.0.0b06:*:*:*:*:*:*:*
cpe:2.3:o:zte:mf971r_firmware:2v1.0.0b03:*:*:*:*:*:*:*
cpe:2.3:o:zte:mf971r_firmware:s2v1.0.0b03:*:*:*:*:*:*:*
cpe:2.3:o:zte:mf971r_firmware:sv1.0.0b05:*:*:*:*:*:*:*

More vulnerabilities in Zte Mf971r Firmware

CVE-2021-21749 — Critical (CVSS 9.8): ZTE MF971R product has two stack-based buffer overflow vulnerabilities. An attacker could exploit the vulnerabilities…
CVE-2021-21748 — Critical (CVSS 9.8): ZTE MF971R product has two stack-based buffer overflow vulnerabilities. An attacker could exploit the vulnerabilities…
CVE-2021-21744 — High (CVSS 7.5): ZTE MF971R product has a configuration file control vulnerability. An attacker could use this vulnerability to modify…
CVE-2021-21747 — Medium (CVSS 6.1): ZTE MF971R product has reflective XSS vulnerability. An attacker could use the vulnerability to obtain cookie…
CVE-2021-21746 — Medium (CVSS 6.1): ZTE MF971R product has reflective XSS vulnerability. An attacker could use the vulnerability to obtain cookie…
CVE-2021-21745 — Medium (CVSS 4.3): ZTE MF971R product has a Referer authentication bypass vulnerability. Without CSRF verification, an attackercould use…

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