Answer in brief
CVE-2021-27137 records a High severity (CVSS 8.1) vulnerability in CISA ADP Vulnrichment. The current sources mark it as known exploited. The current feed maps DD-WRT/DD-WRT (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.1. Known-exploitation status makes exposure review time-sensitive. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps DD-WRT/DD-WRT (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| DD-WRT/DD-WRTgeneric | >=0 <45724 | 45724 |
Published upstream
Jul 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 16, 2026
Added to CISA KEV
Jul 21, 2026
Evidence: source:kev:kev:kev:recordAn 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).
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2021-27137 records a High severity (CVSS 8.1) vulnerability in CISA ADP Vulnrichment. The current sources mark it as known exploited. The current feed maps DD-WRT/DD-WRT (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.1. Known-exploitation status makes exposure review time-sensitive. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps DD-WRT/DD-WRT (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| DD-WRT/DD-WRTgeneric | >=0 <45724 | 45724 |
Published upstream
Jul 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 16, 2026
Added to CISA KEV
Jul 21, 2026
Evidence: source:kev:kev:kev:recordAn 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).
Quoted source text, attributed separately from HOL analysis.