Actively exploited vulnerability
ASUS RT-AX55 Routers: code execution flaw under attack
CVE-2023-39780 · ASUS RT-AX55 Routers OS Command Injection Vulnerability
What is affected
ASUS RT-AX55 Routers are the kind of equipment many homes and small offices run for years without touching: a router, camera or storage box. Attackers scan the internet for exposed units, and a hijacked one can spy on traffic or be enrolled in a botnet without any visible sign.
ASUS RT-AX55 devices contain an OS command injection vulnerability that could allow a remote, authenticated attacker to execute arbitrary commands. As represented by CVE-2023-41346.
What an attacker can do
This is a code execution flaw. It lets an attacker run their own commands or programs on the affected system. In practice that usually means taking it over: installing malware, stealing data or using it to reach other devices on the same network.
- How it is reached
- Over the internet or network
- Access the attacker needs
- A basic user account
- Does the victim have to do something?
- No, works without the victim doing anything
What to do
- Check whether you own this device: look at the label on your router, camera or NAS, or open its admin page and note the model and firmware version.
- Install the latest firmware from the manufacturer's support page or the device's own update menu.
- If the manufacturer no longer releases updates for the model, replace it. An end-of-life device with an exploited flaw cannot be made safe.
- Turn off remote administration from the internet unless you truly need it, and change the default admin password.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vendor advisories and fixes
How urgent is it
CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on June 2, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by June 23, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.
The EPSS model estimates a 40% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 99% of all scored vulnerabilities.
Its CVSS severity score is 8.8 out of 10 (high), as recorded in the US National Vulnerability Database.
Technical description
On ASUS RT-AX55 3.0.0.4.386.51598 devices, authenticated attackers can perform OS command injection via the /start_apply.htm qos_bw_rulelist parameter. NOTE: for the similar "token-generated module" issue, see CVE-2023-41345; for the similar "token-refresh module" issue, see CVE-2023-41346; for the similar "check token module" issue, see CVE-2023-41347; and for the similar "code-authentication module" issue, see CVE-2023-41348.