CyberSecBulletin
CVE-2024-41338NVD status: Modified

Vigor165 Firmware: NULL Pointer Dereference

Published Updated By the CyberSecBulletin desk

CVE-2024-41338 is a high-severity NULL pointer dereference vulnerability in Vigor165 Firmware from DrayTek, with a CVSS 3.1 base score of 7.5 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 4.2.6 as the first without the flaw, so updating Vigor165 Firmware to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.45% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Vigor165 Firmware to 4.2.6 or a later version.
  2. Update Vigor166 Firmware to 4.2.6 or a later version.
  3. Update Vigor2620 Firmware to 3.9.8.8 or a later version.
  4. 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
DraytekVigor165 Firmwarebefore 4.2.64.2.6
DraytekVigor166 Firmwarebefore 4.2.64.2.6
DraytekVigor2620 Firmwarebefore 3.9.8.83.9.8.8
DraytekVigorlte200 Firmwarebefore 3.9.8.83.9.8.8
DraytekVigor2860 Firmwarebefore 3.9.73.9.7
DraytekVigor2925 Firmwarebefore 3.9.73.9.7
DraytekVigor2862 Firmwarebefore 3.9.9.43.9.9.4
DraytekVigor2926 Firmwarebefore 3.9.9.43.9.9.4
DraytekVigor2133 Firmwarebefore 3.9.83.9.8
DraytekVigor2762 Firmwarebefore 3.9.83.9.8
DraytekVigor2832 Firmwarebefore 3.9.83.9.8
DraytekVigor2135 Firmwarebefore 4.4.5.14.4.5.1
DraytekVigor2765 Firmwarebefore 4.4.5.14.4.5.1
DraytekVigor2766 Firmwarebefore 4.4.5.14.4.5.1
DraytekVigor2865 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2866 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2927 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2962 Firmwarebefore 4.3.2.74.3.2.7
DraytekVigor3910 Firmwarebefore 4.3.2.74.3.2.7
DraytekVigor3912 Firmwarebefore 4.3.5.24.3.5.2

Version data comes from NVD's product matching. 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
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

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

Official description

A NULL pointer dereference in Draytek devices Vigor 165/166 prior to v4.2.6 , Vigor 2620/LTE200 prior to v3.9.8.8, Vigor 2860/2925 prior to v3.9.7, Vigor 2862/2926 prior to v3.9.9.4, Vigor 2133/2762/2832 prior to v3.9.8, Vigor 2135/2765/2766 prior to v4.4.5.1, Vigor 2865/2866/2927 prior to v4.4.5.3, Vigor 2962/3910 prior to v4.3.2.7, Vigor 3912 prior to v4.3.5.2, and Vigor 2925 up to v3.9.6 allows attackers to cause a Denial of Service (DoS) via a crafted DHCP request.

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

The underlying weakness: NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

How developers prevent this class of flaw

  • For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
  • Select a programming language that is not susceptible to these issues.
  • Check the results of all functions that return a value and verify that the value is non-null before acting upon it.

More NULL Pointer Dereference vulnerabilities (CWE-476)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Vigor165 Firmware

All Vigor165 Firmware vulnerabilities

Recent NULL Pointer Dereference vulnerabilities

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