ASUS RT-AX55 Routers OS Command Injection
CVE-2023-39780 is a high-severity improper neutralization of special elements used in an OS command vulnerability in RT-AX55 from ASUS, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected RT-AX55 versions: 3.0.0.4.386.51598. The record does not name a fixed version, so check the vendor advisory. CISA added it to the Known Exploited Vulnerabilities catalogue on June 2, 2025, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Check which version of RT-AX55 you run against the affected versions below, and install the vendor's latest release.
- CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| ASUS | RT-AX55 | 3.0.0.4.386.51598 | Not stated |
| ASUS | Rt-ax55 Firmware | 3.0.0.4.386.51598 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA (mitre.org) |
| CVSS 3.1 | 8.8 | High | NVD |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements used in an OS Command
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.
How developers prevent this class of flaw
- If at all possible, use library calls rather than external processes to recreate the desired functionality.
- For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Improper Neutralization of Special Elements used in an OS Command vulnerabilities (CWE-78)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-39780US Government Resource
Technical write-ups (may include proof of concept)
- github.com/D2y6p/CVE/blob/main/asus/CVE-2023-39780/1/EN.mdExploit, Third Party Advisory
- github.com/D2y6p/CVE/blob/main/asus/CVE-2023-39780/2/EN.mdExploit, Third Party Advisory
- github.com/D2y6p/CVE/blob/main/asus/CVE-2023-39780/3/EN.mdExploit, Third Party Advisory
- github.com/D2y6p/CVE/blob/main/asus/CVE-2023-39780/4/EN.mdExploit, Third Party Advisory
- github.com/D2y6p/CVE/blob/main/asus/CVE-2023-39780/5/EN.mdExploit, Third Party Advisory
- github.com/D2y6p/CVE/blob/main/asus/CVE-2023-39780/6/EN.mdExploit, Third Party Advisory
- greynoise.io/blog/stealthy-backdoor-campaign-affecting-asus-routersExploit, Third Party Advisory
Other vulnerabilities in RT-AX55
- 7.2 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 7.2 High severity
Recent Improper Neutralization of Special Elements used in an OS Command vulnerabilities
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
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