CVE-2021-27137
KEVHIGH 8.1EPSS 4.0%
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).
- CVSS v3.1
- 8.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS
- 4.00% chance of exploitation in the next 30 days, 90th percentile
- CISA KEV
- added 2026-07-21
- Published
- 2026-07-16
- Updated
- 2026-07-22