Vulnerability-Lookup

BDU:2026-11945 (CVE-2021-27137)

Vulnerability from fstec – Published: 2026-08-19 – Updated: 2026-08-19 – View on bdu.fstec.ru Exploit publicly available Yes No remediation information

Title

Уязвимость службы UPnP микропрограммного обеспечения маршрутизаторов DD-WRT, позволяющая нарушителю вызвать отказ в обслуживании

Summary

Уязвимость службы UPnP микропрограммного обеспечения маршрутизаторов DD-WRT связана с переполнением буфера в стеке. Эксплуатация уязвимости может позволить нарушителю, действующему удаленно, вызвать отказ в обслуживании с помощью специально созданных запросов через UDP-порт

Severity

10.0 (High) CVSS 2.0


                      
                        AV:N/AC:L/Au:N/C:C/I:C/A:C

9.8 (Critical) CVSS 3.1


                      
                        CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Class

Code vulnerability

Status

Potential vulnerability

Exploitation

Data structure manipulation

Incidents

Yes

Remediation

Being clarified

CWE

CWE-121 - Переполнение буфера в стеке

Aliases

CVE-2021-27137, PT-2026-46055

References

6 references

URL
https://dbugs.ptsecurity.com/vulnerability/CVE-2021-27137
https://www.fortinet.com/blog/threat-research/inside-cross-platform-propagation…
https://dailysecurityreview.com/resources/c0xmo-botnet-exploits-dd-wrt-cve-2021…
https://cybersecuritynews.com/new-gafgyt-variant-targets-multiple-linux-archite…
https://www.bleepingcomputer.com/news/security/c0xmo-botnet-spreads-via-dd-wrt-…
https://www.cisa.gov/sites/default/files/csv/known_exploited_vulnerabilities.csv

Impacted products

1 product from 1 vendor

Vendors

GNU General Public License

Products

DD-WRT

Versions

до 45723 включительно (DD-WRT)

Product types

Firmware

Mitigations

Компенсирующие меры: - использование средств межсетевого экранирования для ограничения удалённого доступа; - ограничение доступа из внешних сетей (Интернет); - соблюдение парольной политики принятой для организации доступа к устройству; - сегментирование сети для ограничения доступа к уязвимому устройству; - полное отключение службы UPnP (Internet Gateway Device Protocol)

Credits

Данная уязвимость получила название C0XMO.

JSON

To clipboard

{
  "CVSS 2.0": "AV:N/AC:L/Au:N/C:C/I:C/A:C",
  "CVSS 3.0": "AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
  "CVSS 4.0": null,
  "remediation_\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": null,
  "remediation_\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435": null,
  "\u0412\u0435\u043d\u0434\u043e\u0440 \u041f\u041e": "GNU General Public License",
  "\u0412\u0435\u0440\u0441\u0438\u044f \u041f\u041e": "\u0434\u043e 45723 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e (DD-WRT)",
  "\u0412\u043e\u0437\u043c\u043e\u0436\u043d\u044b\u0435 \u043c\u0435\u0440\u044b \u043f\u043e \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044e": "\u041a\u043e\u043c\u043f\u0435\u043d\u0441\u0438\u0440\u0443\u044e\u0449\u0438\u0435 \u043c\u0435\u0440\u044b:\n- \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u0441\u0440\u0435\u0434\u0441\u0442\u0432 \u043c\u0435\u0436\u0441\u0435\u0442\u0435\u0432\u043e\u0433\u043e \u044d\u043a\u0440\u0430\u043d\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u044f \u0434\u043b\u044f \u043e\u0433\u0440\u0430\u043d\u0438\u0447\u0435\u043d\u0438\u044f \u0443\u0434\u0430\u043b\u0451\u043d\u043d\u043e\u0433\u043e \u0434\u043e\u0441\u0442\u0443\u043f\u0430;\n- \u043e\u0433\u0440\u0430\u043d\u0438\u0447\u0435\u043d\u0438\u0435 \u0434\u043e\u0441\u0442\u0443\u043f\u0430 \u0438\u0437 \u0432\u043d\u0435\u0448\u043d\u0438\u0445 \u0441\u0435\u0442\u0435\u0439 (\u0418\u043d\u0442\u0435\u0440\u043d\u0435\u0442); \n- \u0441\u043e\u0431\u043b\u044e\u0434\u0435\u043d\u0438\u0435 \u043f\u0430\u0440\u043e\u043b\u044c\u043d\u043e\u0439 \u043f\u043e\u043b\u0438\u0442\u0438\u043a\u0438 \u043f\u0440\u0438\u043d\u044f\u0442\u043e\u0439 \u0434\u043b\u044f \u043e\u0440\u0433\u0430\u043d\u0438\u0437\u0430\u0446\u0438\u0438 \u0434\u043e\u0441\u0442\u0443\u043f\u0430 \u043a \u0443\u0441\u0442\u0440\u043e\u0439\u0441\u0442\u0432\u0443; \n- \u0441\u0435\u0433\u043c\u0435\u043d\u0442\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 \u0441\u0435\u0442\u0438 \u0434\u043b\u044f \u043e\u0433\u0440\u0430\u043d\u0438\u0447\u0435\u043d\u0438\u044f \u0434\u043e\u0441\u0442\u0443\u043f\u0430 \u043a \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u043c\u0443 \u0443\u0441\u0442\u0440\u043e\u0439\u0441\u0442\u0432\u0443;\n- \u043f\u043e\u043b\u043d\u043e\u0435 \u043e\u0442\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u0435 \u0441\u043b\u0443\u0436\u0431\u044b UPnP (Internet Gateway Device Protocol)",
  "\u0414\u0430\u0442\u0430 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0438\u044f": "03.06.2026",
  "\u0414\u0430\u0442\u0430 \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0433\u043e \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f": "19.08.2026",
  "\u0414\u0430\u0442\u0430 \u043f\u0443\u0431\u043b\u0438\u043a\u0430\u0446\u0438\u0438": "19.08.2026",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": "BDU:2026-11945",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440\u044b \u0434\u0440\u0443\u0433\u0438\u0445 \u0441\u0438\u0441\u0442\u0435\u043c \u043e\u043f\u0438\u0441\u0430\u043d\u0438\u0439 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "CVE-2021-27137, PT-2026-46055",
  "\u0418\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0438": "\u0418\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0438 \u043e\u0442\u0441\u0443\u0442\u0441\u0442\u0432\u0443\u0435\u0442",
  "\u041a\u043b\u0430\u0441\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043a\u043e\u0434\u0430",
  "\u041d\u0430\u0437\u0432\u0430\u043d\u0438\u0435 \u041f\u041e": "DD-WRT",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u041e\u0421 \u0438 \u0442\u0438\u043f \u0430\u043f\u043f\u0430\u0440\u0430\u0442\u043d\u043e\u0439 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u044b": null,
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0441\u043b\u0443\u0436\u0431\u044b UPnP \u043c\u0438\u043a\u0440\u043e\u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f \u043c\u0430\u0440\u0448\u0440\u0443\u0442\u0438\u0437\u0430\u0442\u043e\u0440\u043e\u0432 DD-WRT, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u0432\u044b\u0437\u0432\u0430\u0442\u044c \u043e\u0442\u043a\u0430\u0437 \u0432 \u043e\u0431\u0441\u043b\u0443\u0436\u0438\u0432\u0430\u043d\u0438\u0438",
  "\u041d\u0430\u043b\u0438\u0447\u0438\u0435 \u044d\u043a\u0441\u043f\u043b\u043e\u0439\u0442\u0430": "\u0421\u0443\u0449\u0435\u0441\u0442\u0432\u0443\u0435\u0442 \u0432 \u043e\u0442\u043a\u0440\u044b\u0442\u043e\u043c \u0434\u043e\u0441\u0442\u0443\u043f\u0435",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "\u041f\u0435\u0440\u0435\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u0435 \u0431\u0443\u0444\u0435\u0440\u0430 \u0432 \u0441\u0442\u0435\u043a\u0435 (CWE-121)",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0441\u043b\u0443\u0436\u0431\u044b UPnP \u043c\u0438\u043a\u0440\u043e\u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f \u043c\u0430\u0440\u0448\u0440\u0443\u0442\u0438\u0437\u0430\u0442\u043e\u0440\u043e\u0432 DD-WRT \u0441\u0432\u044f\u0437\u0430\u043d\u0430 \u0441 \u043f\u0435\u0440\u0435\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u0435\u043c \u0431\u0443\u0444\u0435\u0440\u0430 \u0432 \u0441\u0442\u0435\u043a\u0435. \u042d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043c\u043e\u0436\u0435\u0442 \u043f\u043e\u0437\u0432\u043e\u043b\u0438\u0442\u044c \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e, \u0434\u0435\u0439\u0441\u0442\u0432\u0443\u044e\u0449\u0435\u043c\u0443 \u0443\u0434\u0430\u043b\u0435\u043d\u043d\u043e, \u0432\u044b\u0437\u0432\u0430\u0442\u044c \u043e\u0442\u043a\u0430\u0437 \u0432 \u043e\u0431\u0441\u043b\u0443\u0436\u0438\u0432\u0430\u043d\u0438\u0438 \u0441 \u043f\u043e\u043c\u043e\u0449\u044c\u044e \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u043e \u0441\u043e\u0437\u0434\u0430\u043d\u043d\u044b\u0445 \u0437\u0430\u043f\u0440\u043e\u0441\u043e\u0432 \u0447\u0435\u0440\u0435\u0437 UDP-\u043f\u043e\u0440\u0442",
  "\u041f\u043e\u0441\u043b\u0435\u0434\u0441\u0442\u0432\u0438\u044f \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": null,
  "\u041f\u0440\u043e\u0447\u0430\u044f \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f": "\u0414\u0430\u043d\u043d\u0430\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043f\u043e\u043b\u0443\u0447\u0438\u043b\u0430 \u043d\u0430\u0437\u0432\u0430\u043d\u0438\u0435 C0XMO.",
  "\u0421\u0432\u044f\u0437\u044c \u0441 \u0438\u043d\u0446\u0438\u0434\u0435\u043d\u0442\u0430\u043c\u0438 \u0418\u0411": "\u0414\u0430",
  "\u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u0430",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044f": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438": "\u041c\u0430\u043d\u0438\u043f\u0443\u043b\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 \u0441\u0442\u0440\u0443\u043a\u0442\u0443\u0440\u0430\u043c\u0438 \u0434\u0430\u043d\u043d\u044b\u0445",
  "\u0421\u0441\u044b\u043b\u043a\u0438 \u043d\u0430 \u0438\u0441\u0442\u043e\u0447\u043d\u0438\u043a\u0438": "https://dbugs.ptsecurity.com/vulnerability/CVE-2021-27137\nhttps://www.fortinet.com/blog/threat-research/inside-cross-platform-propagation-of-new-gafgyt-variant-c0xmo\nhttps://dailysecurityreview.com/resources/c0xmo-botnet-exploits-dd-wrt-cve-2021-27137-evicts-rival-malware/\nhttps://cybersecuritynews.com/new-gafgyt-variant-targets-multiple-linux-architectures/\nhttps://www.bleepingcomputer.com/news/security/c0xmo-botnet-spreads-via-dd-wrt-router-flaw-kills-rival-malware/\nhttps://www.cisa.gov/sites/default/files/csv/known_exploited_vulnerabilities.csv",
  "\u0421\u0442\u0430\u0442\u0443\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041f\u043e\u0442\u0435\u043d\u0446\u0438\u0430\u043b\u044c\u043d\u0430\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c",
  "\u0422\u0438\u043f \u041f\u041e": "\u041c\u0438\u043a\u0440\u043e\u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u044b\u0439 \u043a\u043e\u0434",
  "\u0422\u0438\u043f \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "CWE-121",
  "\u0423\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041a\u0440\u0438\u0442\u0438\u0447\u0435\u0441\u043a\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 2.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 10)\n\u041a\u0440\u0438\u0442\u0438\u0447\u0435\u0441\u043a\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 3.1 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 9,8)"
}

CVE-2021-27137 (GCVE-0-2021-27137)

Vulnerability from cvelistv5 – Published: 2026-07-16 00:00 – Updated: 2026-07-22 03:55

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)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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 mitre root

References

6 references

URL	Tags
https://svn.dd-wrt.com/changeset/45724
https://ssd-disclosure.com/ssd-advisory-dd-wrt-up…
https://securityaffairs.com/193290/uncategorized/…
https://www.bleepingcomputer.com/news/security/c0…
https://www.fortinet.com/blog/threat-research/ins…
https://www.cisa.gov/known-exploited-vulnerabilit…	government-resource

Impacted products

1 product

Vendor	Product	Version
DD-WRT	DD-WRT	Affected: 0 , < 45724 (custom) cpe:2.3:a:dd-wrt:dd-wrt::::::::

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-27137",
                "options": [
                  {
                    "Exploitation": "active"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
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.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.