ASUS Router: Active debug code enables Telnet with root privileges
Summary
Certain ASUS router firmware series contain an Active Debug Code vulnerability (CWE-489). A remote, authenticated user can send a crafted HTTP request to bypass security mechanisms and enable the Telnet service. The attacker can then execute arbitrary commands with root privileges, which may also affect other devices connected to the router. Exploitation requires valid credentials and high privileges.
Affected
- ASUS Router firmware 3.0.0.4_386 series
- ASUS Router firmware 3.0.0.4_388 series
- ASUS Router firmware 3.0.0.6_102 series
- Check the ASUS advisory for the exact model list. The CNA record states the default configuration is unaffected.
Fixed in
Unknown. ASUS has published firmware updates for the affected series, but the fixed build numbers could not be verified. Check the ASUS Security Advisory for the fixed versions.
Workaround
- Isolate the router management interface to trusted networks only.
- Do not expose the web management interface to the internet and disable WAN-side administration.
- Set a strong, unique admin password with at least 10 characters, including uppercase letters, numbers and symbols.
- Block inbound Telnet (TCP/23) at the upstream firewall.
Exploitation
- No confirmed exploitation in the wild.
- No public proof-of-concept code found.
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
- Not verified as listed in the CISA KEV catalog.
Our recommendation
- Inventory all ASUS routers and record model and firmware build.
- Check each model against the ASUS advisory; plan replacement for end-of-life models that will not receive updates.
- Install the fixed firmware, prioritising devices with remote management or VPN use.
- Patch CVE-2026-14157 at the same time, as the same advisory covers it.
- Check for an unexpected Telnet listener on TCP/23 and review admin logs for unusual activity.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- ASUS Security Advisory www.asus.com
- SentinelOne CVE-2026-13313 vulnerability database www.sentinelone.com
- VulDB CVE-2026-13313 vuldb.com
- OpenCVE CVE-2026-13313 app.opencve.io
- Tom's Hardware: malicious VPN config files and Telnet flaw on ASUS routers www.tomshardware.com
- BeyondMachines: ASUS patches critical router vulnerabilities beyondmachines.net
- SecurityOnline: ASUS security vulnerabilities securityonline.info
- Windows Forum: ASUS router CVE-2026-14157 and CVE-2026-13313 windowsforum.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 08:35.
Original description (NVD)
An Active Debug Code vulnerability in certain ASUS router models allows a remote authenticated user, via a crafted HTTP request, to bypass security mechanisms and enable the Telnet service, thereby executing arbitrary commands with root privileges and potentially affecting other devices connected to the router. Refer to the ' Security Update for ASUS Router Firmware ' section on the ASUS Security Advisory for more information.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.