What is the CVSS score of CVE-2021-27256?

CVE-2021-27256 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.9%.

Is there a patch available for CVE-2021-27256?

Yes, a patch is available for CVE-2021-27256. Update the affected software to the latest version immediately.

Br200 Firmware CVE-2021-27256

HIGH

OS Command Injection (CWE-78)

2021-03-05 zdi-disclosures@trendmicro.com

Netgear RCE Command Injection Br200 Firmware Br500 Firmware D7800 Firmware Ex6100V2 Firmware Ex6150V2 Firmware Ex6250 Firmware Ex6400 Firmware Ex6400V2 Firmware Ex6410 Firmware Ex6420 Firmware Ex7300 Firmware Ex7300V2 Firmware Ex7320 Firmware Ex7700 Firmware Ex8000 Firmware Lbr20 Firmware R7800 Firmware R8900 Firmware R9000 Firmware Rbk12 Firmware Rbk13 Firmware Rbk14 Firmware Rbk15 Firmware Rbk20 Firmware Rbk23 Firmware Rbk40 Firmware Rbk43 Firmware Rbk43S Firmware Rbk44 Firmware Rbk50 Firmware Rbk53 Firmware Rbr10 Firmware Rbr20 Firmware Rbr40 Firmware Rbr50 Firmware Rbs10 Firmware Rbs20 Firmware Rbs40 Firmware Rbs50 Firmware Rbs50Y Firmware Xr450 Firmware Xr500 Firmware Xr700 Firmware

8.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

8.8 HIGH

AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

CVE Published

Mar 05, 2021 - 20:15 nvd

HIGH 8.8

DescriptionNVD

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R7800 firmware version 1.0.2.76. Although authentication is required to exploit this vulnerability, the existing authentication mechanism can be bypassed. The specific flaw exists within the handling of the rc_service parameter provided to apply_save.cgi. The issue results from the lack of proper validation of a user-supplied string before using it to execute a system call. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-12355.

AnalysisAI

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R7800 firmware version 1.0.2.76. Rated high severity (CVSS 8.8), this vulnerability is no authentication required, low attack complexity. This OS Command Injection vulnerability could allow attackers to execute arbitrary operating system commands on the host.

Technical ContextAI

This vulnerability is classified as OS Command Injection (CWE-78), which allows attackers to execute arbitrary operating system commands on the host. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R7800 firmware version 1.0.2.76. Although authentication is required to exploit this vulnerability, the existing authentication mechanism can be bypassed. The specific flaw exists within the handling of the rc_service parameter provided to apply_save.cgi. The issue results from the lack of proper validation of a user-supplied string before using it to execute a system call. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-12355. Affected products include: Netgear Br200 Firmware, Netgear Br500 Firmware, Netgear D7800 Firmware, Netgear Ex6100V2 Firmware, Netgear Ex6150V2 Firmware. Version information: version 1.0.2.76..

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Avoid passing user input to shell commands. Use language-specific APIs instead of shell execution. Apply strict input validation with allowlists.