01 Record
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
HighKEVPUBLISHEDCNA: mitre
CNA base score8.1 CVSS v3.xCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
02 Description
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
03 Exploitation and scoring
- Exploitation
- Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalog on 2026-07-21. Federal remediation due 2026-07-24.
- SSVC decision
- ExploitationactiveCISA reports credible evidence of active exploitation.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
- EPSS probability
- 3.99% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 90.2% of scored records. A rank, not a probability.
- NVD base score
- 8.1 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVD analysis status
- Analyzed. NVD last modified this record on 2026-07-22.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-07-16 00:00Z3 MO AGO
- Last updated
- 2026-07-22 03:55Z3 MO AGO
- Reserved
- 2021-02-10
- Assigning CNA
- mitre
- Record state
- PUBLISHED
- Severity
- High (CVSS 8.1)
- CNA CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weaknesses
- CWE-121Stack-based Buffer OverflowVariant
- Data version
- 5.2
- Document digest
- b59d0a73c787f5f0780c3d39b0f636617afc23b091f8761cbbe2ab833b48c623
05 Affected products
VendorProductVersionsPlatforms
06 References
- svn.dd-wrt.comhttps://svn.dd-wrt.com/changeset/45724
- ssd-disclosure.comhttps://ssd-disclosure.com/ssd-advisory-dd-wrt-upnp-buffer-overflow/
- securityaffairs.comhttps://securityaffairs.com/193290/uncategorized/iot-botnet-c0xmo-adds-competitor-killing-capability.html
- www.bleepingcomputer.comhttps://www.bleepingcomputer.com/news/security/c0xmo-botnet-spreads-via-dd-wrt-router-flaw-kills-rival-malware/
- www.fortinet.comhttps://www.fortinet.com/blog/threat-research/inside-cross-platform-propagation-of-new-gafgyt-variant-c0xmo
- www.cisa.govhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27137