ASUSWRT router firmware: Buffer overflow via HTTP request causes denial of service
Summary
CVE-2026-17518 is a buffer overflow (CWE-121) in certain ASUS router models running ASUSWRT 3.0.0.4_386 or 3.0.0.4_388 firmware. An adjacent, authenticated user can send an HTTP request with input longer than expected, which can corrupt device operations and cause a denial of service. Exploitation requires high privileges and adjacent network access, and no public exploit has been reported.
Affected
- ASUS router models running ASUSWRT 3.0.0.4_386 series
- ASUS router models running ASUSWRT 3.0.0.4_388 series
- Default configuration is unaffected according to the CNA record
Fixed in
Unknown. The vendor advisory is referenced, but no fixed firmware version could be confirmed from the available sources.
Workaround
Unknown.
Exploitation
- No known exploitation in the wild.
- CISA SSVC: exploitation none, automatable no, technical impact partial.
- Attack requires adjacent network access and high privileges.
Our recommendation
- Check whether your ASUS router runs an affected ASUSWRT 3.0.0.4_386 or 3.0.0.4_388 firmware version.
- Check the ASUS Security Advisory for an updated firmware and install it as soon as it is available.
- Restrict administrative access to the router to trusted users and networks.
- If no update exists for an affected model, consider replacing the device with a supported model.
- Monitor the device for unexpected restarts or loss of service.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- ASUS Security Advisory www.asus.com
- OpenCVE: CVE-2026-17518 app.opencve.io
- VulDB: CVE-2026-17518 vuldb.com
- Threat Intelligence: CVE-2026-17518 cve.threatint.com
- Strix: CVE-2026-17518 www.strix.ai
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 1 Nov 2026, 15:37.
Original description (NVD)
Buffer Copy without Checking Size of Input in certain ASUS router models allows an adjacent authenticated user to corrupt device operations and cause a denial of service via an HTTP request with input exceeding the expected length. 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.
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