Description
An issue was discovered in router/upnp/src/ssdp.c in DD-WRT before 45724. An unsafe strcpy in the UPnP handling functionality allows an unauthenticated remote attacker to send a request that would overflow an internal fixed buffer. Exploitation requires the DD-WRT user to enable UPnP (which is off by default, and only listens on internal interfaces by default). This occurs in ssdp_msearch (reachable by an M-SEARCH request).
Metrics
CVSS 3.1 8.1/10
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| DD-WRT | DD-WRT | < 45724 |
References
- https://securityaffairs.com/193290/uncategorized/iot-botnet-c0xmo-adds-competitor-killing-capability.htmlExploit, Third Party Advisory
- https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/Exploit, Third Party Advisory
- https://svn.dd-wrt.com/changeset/45724Patch
- https://www.bleepingcomputer.com/news/security/c0xmo-botnet-spreads-via-dd-wrt-router-flaw-kills-rival-malware/Exploit, Third Party Advisory
- https://www.fortinet.com/blog/threat-research/inside-cross-platform-propagation-of-new-gafgyt-variant-c0xmoExploit
- https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/Exploit, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27137US Government Resource
Timeline
- Published
- Jul 16, 2026
- Last modified
- Jul 22, 2026
- Added to CISA KEV
- Jul 21, 2026
- NVD status
- Analyzed