CVE-2021-27691
CVE-2021-27691 is a critical-severity vulnerability in Tendacn G0 Firmware with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 25% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-78.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v2: 10.0
- EPSS exploit prediction: 25% (98th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-78
- Affected product: Tendacn G0 Firmware
- Published:
- Last modified:
Description
Command Injection in Tenda G0 routers with firmware versions v15.11.0.6(9039)_CN and v15.11.0.5(5876)_CN , and Tenda G1 and G3 routers with firmware versions v15.11.0.17(9502)_CN or v15.11.0.16(9024)_CN allows remote attackers to execute arbitrary OS commands via a crafted action/setDebugCfg request. This occurs because the "formSetDebugCfg" function executes glibc's system function with untrusted input.
Frequently asked questions
- What is CVE-2021-27691?
- Command Injection in Tenda G0 routers with firmware versions v15.11.0.6(9039)_CN and v15.11.0.5(5876)_CN , and Tenda G1 and G3 routers with firmware versions v15.11.0.17(9502)_CN or v15.11.0.16(9024)_CN allows remote attackers to execute arbitrary OS commands via a crafted action/setDebugCfg request. This occurs because the "formSetDebugCfg" function executes glibc's system function with untrusted input.
- How severe is CVE-2021-27691?
- CVE-2021-27691 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2021-27691 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 25% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-27691?
- CVE-2021-27691 primarily affects Tendacn G0 Firmware. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2021-27691?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- When was CVE-2021-27691 published?
- CVE-2021-27691 was published on 2021-04-16 and last updated on 2026-06-17.
References
Affected products (6)
- cpe:2.3:o:tendacn:g0_firmware:15.11.0.5\(5876\)_cn:*:*:*:*:*:*:*
- cpe:2.3:o:tendacn:g0_firmware:15.11.0.6\(9039\)_cn:*:*:*:*:*:*:*
- cpe:2.3:o:tendacn:g1_firmware:15.11.0.16\(9024\)_cn:*:*:*:*:*:*:*
- cpe:2.3:o:tendacn:g1_firmware:15.11.0.17\(9502\)_cn:*:*:*:*:*:*:*
- cpe:2.3:o:tendacn:g3_firmware:15.11.0.16\(9024\)_cn:*:*:*:*:*:*:*
- cpe:2.3:o:tendacn:g3_firmware:15.11.0.17\(9502\)_cn:*:*:*:*:*:*:*
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