Threat intel / CVE tracker
CVE-2021-27137
High KEV · actively exploited PoC availableCVSS base score
8.1
Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HAn 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).
Vendor
dd-wrt
Product
dd-wrt
Affected
dd-wrt dd-wrt
Weakness
CWE-121 · Memory corruption
Published
Jul 16, 2026
Last modified
Jul 22, 2026
CVSS version
v3.1
Views
7
// References & exploits
https://securityaffairs.com/193290/uncategorized/iot-botnet-c0xmo-adds-competitor-killing-capability.htmlPoCThird Party Advisoryhttps://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/PoCThird Party Advisoryhttps://svn.dd-wrt.com/changeset/45724Patchhttps://www.bleepingcomputer.com/news/security/c0xmo-botnet-spreads-via-dd-wrt-router-flaw-kills-rival-malware/PoCThird Party Advisoryhttps://www.fortinet.com/blog/threat-research/inside-cross-platform-propagation-of-new-gafgyt-variant-c0xmoPoChttps://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/PoCThird Party Advisoryhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27137US Government Resource