CVE-2021-21739
CVE-2021-21739 is a medium-severity vulnerability in Zte Zxctn 6120h Firmware with a CVSS 3.x base score of 4.6. 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-345.
Key facts
- Severity: Medium (CVSS 3.x base score 4.6)
- CVSS v2: 2.1
- EPSS exploit prediction: 0% (16th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-345
- Affected product: Zte Zxctn 6120h Firmware
- Published:
- Last modified:
Description
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>
Frequently asked questions
- What is CVE-2021-21739?
- 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>
- How severe is CVE-2021-21739?
- CVE-2021-21739 has a CVSS 3.x base score of 4.6, rated medium severity. It is exploitable over physical access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
- Is CVE-2021-21739 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-21739?
- CVE-2021-21739 affects Zte Zxctn 6120h Firmware. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2021-21739?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2021-21739 published?
- CVE-2021-21739 was published on 2021-08-05 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:o:zte:zxctn_6120h_firmware:5.10.00b24:*:*:*:*:*:*:*
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