Cyber Resilience

CVE-2021-27256

High

Published: 05 March 2021

Published
05 March 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 8.8 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0056 68.6th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-27256 is a high-severity OS Command Injection (CWE-78) vulnerability in Netgear Br200 Firmware. Its CVSS base score is 8.8 (High).

Operationally, ranked in the top 31.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

netgear
br200 firmware
≤ 5.10.0.5
netgear
br500 firmware
≤ 5.10.0.5
netgear
d7800 firmware
≤ 1.0.1.60
netgear
ex6100v2 firmware
≤ 1.0.1.98
netgear
ex6150v2 firmware
≤ 1.0.1.98
netgear
ex6250 firmware
≤ 1.0.0.134
netgear
ex6400 firmware
≤ 1.0.2.158
netgear
ex6400v2 firmware
≤ 1.0.0.134
netgear
ex6410 firmware
≤ 1.0.0.134
netgear
ex6420 firmware
≤ 1.0.0.134
+33 more product configuration(s) — see NVD for full list

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-78

Platform-independent apps typically execute inside a managed runtime or sandbox that restricts direct OS command execution, reducing the ability to exploit OS command injection.

addresses: CWE-78

Validates inputs to block special elements that would alter OS command execution.

References