CyberSecBulletin
CVE-2023-36187NVD status: Modified

r6400v2: Buffer Copy without Checking Size of Input

Published Updated By the CyberSecBulletin desk

CVE-2023-36187 is a critical-severity buffer copy without checking size of input vulnerability in r6400v2 from NETGEAR, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 1.0.4.118 as the first without the flaw, so updating r6400v2 to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.13% chance of exploitation within 30 days, higher than 67% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update r6400v2 to 1.0.4.118 or a later version.
  2. Update Cbr40 Firmware to 2.5.0.24 or a later version.
  3. Update Lax20 Firmware to 1.1.6.34 or a later version.
  4. Read the advisory on kb.netgear.com for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
NETGEARr6400v2before 1.0.4.1181.0.4.118
NETGEARCbr40 Firmwarebefore 2.5.0.242.5.0.24
NETGEARLax20 Firmwarebefore 1.1.6.341.1.6.34
NETGEARMk62 Firmwarebefore 1.1.6.1221.1.6.122
NETGEARMr60 Firmwarebefore 1.1.6.1221.1.6.122
NETGEARMs60 Firmwarebefore 1.1.6.1221.1.6.122
NETGEARRbw30 Firmwarebefore 2.6.2.62.6.2.6
NETGEARR6400 Firmwarebefore 1.0.1.701.0.1.70
NETGEARR6400v2 Firmwarebefore 1.0.4.1181.0.4.118
NETGEARR6700v3 Firmwarebefore 1.0.4.1181.0.4.118
NETGEARR7000 Firmwarebefore 1.0.11.1301.0.11.130
NETGEARR7000p Firmwarebefore 1.3.3.1481.3.3.148
NETGEARRax200 Firmwarebefore 1.0.4.1201.0.4.120
NETGEARRax75 Firmwarebefore 1.0.4.1201.0.4.120
NETGEARRax80 Firmwarebefore 1.0.4.1201.0.4.120
NETGEARRs400 Firmwarebefore 1.5.1.861.5.1.86

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Official description

Buffer Overflow vulnerability in NETGEAR R6400v2 before version 1.0.4.118, allows remote unauthenticated attackers to execute arbitrary code via crafted URL to httpd.

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: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Buffer Copy without Checking Size of Input vulnerabilities

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