CVE-2021-27137
CVSS Score
8.1
EPSS Score
0.0%
EPSS Percentile
0th
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).
| CWE | CWE-121 |
| Vendor | dd-wrt |
| Product | dd-wrt |
| Published | Jul 16, 2026 |
| Last Updated | Jul 16, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
DD-WRT / DD-WRT
0 < 45724
References
svn.dd-wrt.com: https://svn.dd-wrt.com/changeset/45724 ssd-disclosure.com: https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/ securityaffairs.com: https://securityaffairs.com/193290/uncategorized/iot-botnet-c0xmo-adds-competitor-killing-capability.html bleepingcomputer.com: https://www.bleepingcomputer.com/news/security/c0xmo-botnet-spreads-via-dd-wrt-router-flaw-kills-rival-malware/ fortinet.com: https://www.fortinet.com/blog/threat-research/inside-cross-platform-propagation-of-new-gafgyt-variant-c0xmo