CVE-2021-27256 Command injection in R7800
Network-adjacent attackers can execute arbitrary code as root on NETGEAR R7800 routers by exploiting a command injection flaw in the rc_service parameter.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-27256?
CVE-2021-27256 is a high-severity command injection vulnerability in Netgear D7800 Firmware, published on 5 Mar 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-78
Which versions are affected by CVE-2021-27256?
It affects 43 products.
Products include Netgear Br200 Firmware, Netgear Br500 Firmware, Netgear D7800 Firmware, Netgear Ex6100v2 Firmware, Netgear Ex6150v2 Firmware, Netgear Ex6250 Firmware and 37 more.
How do I fix CVE-2021-27256?
No fix has been published for CVE-2021-27256 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2021-27256 being exploited?
There is no known exploitation of CVE-2021-27256 in the wild and no public exploit code.
Other vulnerabilities in Netgear D7800 Firmware
Sources
Also known as GHSA-7j9h-j7vq-452x.