CyberSecBulletin
CVE-2022-27643NVD status: Modified

R6700v3: Buffer Copy without Checking Size of Input

Published Updated By the CyberSecBulletin desk

CVE-2022-27643 is a high-severity buffer copy without checking size of input vulnerability in R6700v3 from NETGEAR, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected R6700v3 versions: 1.0.4.120_10.0.91. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 25.4% chance of exploitation within 30 days, which is in the top 2.02% of all scored CVEs.

Patch this week

EPSS places it among the vulnerabilities most likely to be exploited soon.

What to do

  1. Update R6400 Firmware to 1.0.1.78 or 1.0.4.126, whichever matches your release line, or a later version.
  2. Update R6700 Firmware to 1.0.4.126 or a later version.
  3. Update R6900p Firmware to 1.3.3.148 or a later version.
  4. Read the advisory on kb.netgear.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
NETGEARR6700v31.0.4.120_10.0.91Not stated
NETGEARR6400 Firmwarebefore 1.0.1.78; before 1.0.4.1261.0.1.78, 1.0.4.126
NETGEARR6700 Firmwarebefore 1.0.4.1261.0.4.126
NETGEARR6900p Firmwarebefore 1.3.3.1481.3.3.148
NETGEARR7000 Firmwarebefore 1.0.11.1341.0.11.134
NETGEARR7000p Firmwarebefore 1.3.3.1481.3.3.148
NETGEARR7850 Firmwarebefore 1.0.5.841.0.5.84
NETGEARR7900p Firmwarebefore 1.4.3.881.4.3.88
NETGEARR7960p Firmwarebefore 1.4.3.881.4.3.88
NETGEARR8000 Firmwarebefore 1.0.4.841.0.4.84
NETGEARR8000p Firmwarebefore 1.4.3.881.4.3.88
NETGEARR8500 Firmwarebefore 1.0.2.1581.0.2.158
NETGEARRax200 Firmwarebefore 1.0.6.1381.0.6.138
NETGEARRax75 Firmwarebefore 1.0.6.1381.0.6.138
NETGEARRax80 Firmwarebefore 1.0.6.1381.0.6.138
NETGEARRs400 Firmwarebefore 1.5.1.861.5.1.86
NETGEARR7100lg Firmwarebefore 1.0.0.761.0.0.76
NETGEARWndr3400 Firmwarebefore 1.0.1.441.0.1.44
NETGEARWnr3500l Firmwarebefore 1.2.0.721.2.0.72
NETGEARXr300 Firmwarebefore 1.0.3.721.0.3.72
NETGEARDc112a Firmwarebefore 1.0.0.641.0.0.64
NETGEARD6220 Firmwarebefore 1.0.0.801.0.0.80
NETGEARD6400 Firmwarebefore 1.0.0.1141.0.0.114
NETGEAREx3700 Firmwarebefore 1.0.0.961.0.0.96
NETGEAREx3800 Firmwarebefore 1.0.0.961.0.0.96

Version data comes from the organisation that assigned the CVE; 3 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
AdjacentThe attacker must be on the same local network segment.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.8HighNVD
CVSS 3.08.8HighCNA (trendmicro.com)

Official description

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of NETGEAR R6700v3 1.0.4.120_10.0.91 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of SOAP requests. When parsing the SOAPAction header, the process does not properly validate the length of user-supplied data prior to copying it to a buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-15692.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Buffer Copy without Checking Size of Input

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Buffer Copy without Checking Size of Input vulnerabilities (CWE-120)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in R6700v3

All R6700v3 vulnerabilities

Recent Buffer Copy without Checking Size of Input vulnerabilities

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