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CVE-2021-27239

HIGH
8.8
CVSS Score
Published: March 29, 2021 at 09:05 PM UTC
Updated: June 17, 2026 at 03:44 AM UTC
68 products affected across 1 vendorR6700 FirmwareR7000P FirmwareRBR850 Firmware

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Severity
HIGH8.8
Exploit prediction
EPSS 0.8%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

D6220 Firmware· NETGEAR
95%
v < 1.0.0.68
Affected range stops below 1.0.0.68, so it looks safe — our inference, not a vendor statement
netgear-d6220 (same device)
D6400 Firmware· NETGEAR
95%
v < 1.0.0.102
Affected range stops below 1.0.0.102, so it looks safe — our inference, not a vendor statement
netgear-d6400 (same device)
D7000 Firmware· NETGEAR
95%
v < 1.0.0.66
Affected range stops below 1.0.0.66, so it looks safe — our inference, not a vendor statement
netgear-d7000 (same device)
D8500 Firmware· NETGEAR
95%
v < 1.0.3.60
Affected range stops below 1.0.3.60, so it looks safe — our inference, not a vendor statement
netgear-d8500 (same device)
DC112A Firmware· NETGEAR
95%
v < 1.0.0.54
Affected range stops below 1.0.0.54, so it looks safe — our inference, not a vendor statement
EX7000 Firmware· NETGEAR
95%
v < 1.0.1.94
Affected range stops below 1.0.1.94, so it looks safe — our inference, not a vendor statement
netgear-ex7000 (same device)
EX7500 Firmware· NETGEAR
95%
v < 1.0.0.72
Affected range stops below 1.0.0.72, so it looks safe — our inference, not a vendor statement
netgear-ex7500 (same device)
R6250 Firmware· NETGEAR
95%
v < 1.0.4.48
Affected range stops below 1.0.4.48, so it looks safe — our inference, not a vendor statement
netgear-r6250 (same device)
R6300 Firmware· NETGEAR
95%
v < 1.0.4.50
Affected range stops below 1.0.4.50, so it looks safe — our inference, not a vendor statement
netgear-r6300 (same device)
R6400· NETGEAR
95%
v < 1.0.1.68v < 1.0.4.102
Affected range stops below 1.0.1.68, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.0.4.102, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (2)

x_refsource_MISCVendor Advisory
Source: [email protected]
https://kb.netgear.com/000062820/Security-Advisory-for-Stack-based-Buffer-Overflow-Remote-Code-Execution-Vulnerability-on-Some-Routers-PSV-2020-0432
x_refsource_MISCThird Party AdvisoryVDB Entry
Source: [email protected]
https://www.zerodayinitiative.com/advisories/ZDI-21-206/

CVSS

8.8HIGH[email protected]
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-121

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