CVE-2021-27137 (GCVE-0-2021-27137)
Vulnerability from cvelistv5 – Published: 2026-07-16 00:00 – Updated: 2026-07-22 03:55
VLAI
EPSS
VEX
Summary
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).
Severity
8.1 (High)
SSVC
Exploitation: active
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-21 00:00 UTC
CWE
- CWE-121 - Stack-based Buffer Overflow
Assigner
mitre
CNA
References
6 references
Impacted products
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Nomenclature
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
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