CVE-2021-27137
criticalpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.040 · 90 %ileEURUUSadded 2026-07-21remediate by 2026-07-24
required action Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
EPSS · scored 2026-10-24
DD-WRT Stack-Based Buffer Overflow Vulnerability
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 8.1–9.8
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (3)
Products and version ranges known to be affected.
also known as (5)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (16)
External citations — patches, advisories, analysis.
- https://securityaffairs.com/193290/uncategorized/iot-botnet-c0xmo-adds-competitor-killing-capability.htmlcnnvd
- https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/cnnvd
- https://svn.dd-wrt.com/changeset/45724cnnvd
- https://www.bleepingcomputer.com/news/security/c0xmo-botnet-spreads-via-dd-wrt-router-flaw-kills-rival-malware/cnnvd
- https://www.fortinet.com/blog/threat-research/inside-cross-platform-propagation-of-new-gafgyt-variant-c0xmocnnvd
- https://securityaffairs.com/193290/uncategorized/iot-botnet-c0xmo-adds-competitor-killing-capability.htmlenisa_euvd
- https://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/enisa_euvd
- https://svn.dd-wrt.com/changeset/45724enisa_euvd
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