CyberSecBulletin
CVE-2024-41596NVD status: Analyzed

vigor3910_firmware: Buffer Copy without Checking Size of Input

Published Updated By the CyberSecBulletin desk

CVE-2024-41596 is a high-severity buffer copy without checking size of input vulnerability in vigor3910_firmware from DrayTek, with a CVSS 3.1 base score of 8.0 out of 10. It can be exploited from the same local network by an attacker with a low-privileged account, without any action from a user. Affected vigor3910_firmware versions: 4.3.2.6 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.33% 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 Vigor2915 Firmware to 4.4.5.3 or a later version.
  2. Update Vigor2866 Firmware to 4.4.5.2 or a later version.
  3. Update Vigor2766 Firmware to 4.4.5.3 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
Draytekvigor3910_firmware4.3.2.6 and earlierNot stated
DraytekVigor2620 FirmwareNot specified in the recordNot stated
DraytekVigor2915 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2866 Firmwarebefore 4.4.5.24.4.5.2
DraytekVigor2766 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2865 Firmwarebefore 4.4.5.24.4.5.2
DraytekVigor2765 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2763 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2135 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor166 Firmwarebefore 4.2.74.2.7
DraytekVigor3912 Firmwarebefore 4.3.6.14.3.6.1
DraytekVigor1000b Firmwarebefore 4.3.2.8; 4.4.0.0 up to, but not including, 4.4.3.14.3.2.8, 4.4.3.1
DraytekVigor165 Firmwarebefore 4.2.74.2.7
DraytekVigor2962 Firmwarebefore 4.3.2.8; 4.4.0.0 up to, but not including, 4.4.3.14.3.2.8, 4.4.3.1
DraytekVigorlte200 FirmwareNot specified in the recordNot stated
DraytekVigor2133 FirmwareNot specified in the recordNot stated
DraytekVigor2762 FirmwareNot specified in the recordNot stated
DraytekVigor2832 FirmwareNot specified in the recordNot stated
DraytekVigor2860 FirmwareNot specified in the recordNot stated
DraytekVigor2862 FirmwareNot specified in the recordNot stated
DraytekVigor2925 FirmwareNot specified in the recordNot stated
DraytekVigor2926 FirmwareNot specified in the recordNot stated
DraytekVigor2952 FirmwareNot specified in the recordNot stated
DraytekVigor3220 FirmwareNot specified in the recordNot stated

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
LowA basic user account is enough.
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:L/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).

Official description

Buffer Overflow vulnerabilities exist in DrayTek Vigor310 devices through 4.3.2.6 (in the Vigor management UI) because of improper retrieval and handling of the CGI form parameters.

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: poc, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Patches and release notes

Other vulnerabilities in vigor3910_firmware

All vigor3910_firmware vulnerabilities

Recent Buffer Copy without Checking Size of Input vulnerabilities

Spotted an error? Tell us.