Vulnerability Intelligence Report
DD-WRT Stack-Based Buffer Overflow Vulnerability
CVE-2021-27137
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).
CISA KEV
SSVC: Active Exploitation
CVSS Base Score
8.1
HIGH
Exploitability:2.3
Impact Score:5.9
EPSS Probability:5.45%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
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Authentication
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Weaponization
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SSVC Action
—
Weaknesses (CWE)
CWE-121 ↗CWE-121 Stack-based Buffer Overflow
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| DD-WRT | DD-WRT | 0 < 45724 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | MITRE Corporation · N/A · USA |
| Reserved | 2021-02-10T00:00:00 |
| Published | 2026-07-16T00:00:00 |
| Last Updated | 2026-07-22T03:55:45 |
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