CyberSecBulletin
CVE-2022-27641NVD status: Modified

R6700v3: Integer Overflow or Wraparound

Published Updated By the CyberSecBulletin desk

CVE-2022-27641 is a high-severity integer overflow or wraparound 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 1.23% chance of exploitation within 30 days, higher than 69% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update D7800 Firmware to 1.0.1.68 or a later version.
  2. Update Ex6200 Firmware to 1.0.1.90 or a later version.
  3. Update Ex8000 Firmware to 1.0.1.240 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
NETGEARD7800 Firmwarebefore 1.0.1.681.0.1.68
NETGEAREx6200 Firmwarebefore 1.0.1.901.0.1.90
NETGEAREx8000 Firmwarebefore 1.0.1.2401.0.1.240
NETGEARR6220 Firmwarebefore 1.1.0.1121.1.0.112
NETGEARR6230 Firmwarebefore 1.1.0.1121.1.0.112
NETGEARR6400 Firmwarebefore 1.0.4.1221.0.4.122
NETGEARR6700 Firmwarebefore 1.0.4.1221.0.4.122
NETGEARR7000 Firmwarebefore 1.0.11.1301.0.11.130
NETGEARR7800 Firmwarebefore 1.0.2.901.0.2.90

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
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 NetUSB module. The issue results from the lack of proper validation of user-supplied data, which can result in an integer overflow before allocating a buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-15806.

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

The underlying weakness: Integer Overflow or Wraparound

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

How developers prevent this class of flaw

  • Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. If possible, choose a language or compiler that performs automatic bounds checking.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Use libraries or frameworks that make it easier to handle numbers without unexpected consequences. Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

More Integer Overflow or Wraparound vulnerabilities (CWE-190)

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 Integer Overflow or Wraparound vulnerabilities

Spotted an error? Tell us.