CVE-2021-27239
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected...
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400 and R6700 firmware version 1.0.4.98 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the upnpd service, which listens on UDP port 1900 by default. A crafted MX header field in an SSDP message can trigger an overflow of a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-11851.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400 and R6700 firmware version 1.0.4.98 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the upnpd service, which listens on UDP port 1900 by default. A crafted MX header field in an SSDP message can trigger an overflow of a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-11851.
- Record
CVE-2021-27239- CVSS 3.0
- 8.8 High
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-121
- Updated
- 2026-11-02
EUVDEUVD-2021-14004
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400 and R6700 firmware version 1.0.4.98 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the upnpd service, which listens on UDP port 1900 by default. A crafted MX header field in an SSDP message can trigger an overflow of a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-11851.
- Record
EUVD-2021-14004- CVSS 3.0
- 8.8 High
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-hqww-3wrx-q5gv No score
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected...
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400 and R6700 firmware version 1.0.4.98 routers. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the upnpd service, which listens on UDP port 1900 by default. A crafted MX header field in an SSDP message can trigger an overflow of a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-11851.
- Record
GHSA-hqww-3wrx-q5gv- Weakness
- CWE-121
- Updated
- 2026-11-02
NVD
This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6400 and R6700 firmware version 1.0.4.98 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the upnpd service, which listens on UDP port 1900 by default. A crafted MX header field in an SSDP message can trigger an overflow of a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-11851.
- Record
CVE-2021-27239- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 3.0
- 8.8 High
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 8.3 High
AV:A/AC:L/Au:N/C:C/I:C/A:C - Weakness
- CWE-121
- Updated
- 2026-11-02
Affected products
- netgear r6700 firmware
- netgear d6220 firmware
- netgear d6400 firmware
- netgear d7000 firmware
- netgear d8500 firmware
- netgear dc112a firmware
- netgear ex7000 firmware
- netgear ex7500 firmware
- netgear multiple routers
- netgear r6250 firmware
- netgear r6300 firmware
- netgear r6400 firmware
Show 25 moreShow less
- netgear r6900p firmware
- netgear r7000 firmware
- netgear r7000p firmware
- netgear r7100lg firmware
- netgear r7850 firmware
- netgear r7900 firmware
- netgear r7900p firmware
- netgear r7960p firmware
- netgear r8000 firmware
- netgear r8000p firmware
- netgear r8300 firmware
- netgear r8500 firmware
- netgear rax200 firmware
- netgear rax75 firmware
- netgear rax80 firmware
- netgear rbr750 firmware
- netgear rbr850 firmware
- netgear rbs40v firmware
- netgear rbs750 firmware
- netgear rbs850 firmware
- netgear rs400 firmware
- netgear wndr3400 firmware
- netgear wnr3500l firmware
- netgear xr300 firmware
- bec technologies multiple routers
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, products | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-27239 is a high vulnerability (CVSS 8.8) in Netgear R6700 Firmware, published March 29, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.77%, the 55th percentile. No source names a fixed version.