Vulnerability Analysis
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
Temporal Score:-
EPSS:5.45%
Threat Intelligence Signals
CISA KEV
YES
KEV Date Added
2026-07-21
Ransomware Use
Unknown
KEV Due Date
2026-07-24
VulnCheck In-the-Wild
No
Nuclei Template
No
EPSS Score
5.447%
EPSS Percentile
91.9th pct
GHSA ID
GitHub Severity
HIGH
SSVC Exploitation
Active
SSVC Automatable
No
Vulnerability Class
—
Identity & Timeline
| Status | - |
| Assigning Authority | - |
| CVSS Version / Source | - |
| Reserved | - |
| Published | - |
| Patch Date (date_public) | - |
| Exploit DB Date | - |
| First GitHub PoC Date | - |
| Last Updated | - |
| Time to Patch (Days to fix) | - |
| Exploit Release Gap | - |
| PoC Release Gap | - |
| Exploit DB References | None identified |
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| No affected products specified. | ||
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