CyberSecBulletin
CVE-2024-41593NVD status: Modified

Vigor3912 Firmware: Out-of-bounds Write

Published Updated By the CyberSecBulletin desk

CVE-2024-41593 is a critical-severity out-of-bounds write vulnerability in Vigor3912 Firmware from DrayTek, 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 4.3.6.1 as the first without the flaw, so updating Vigor3912 Firmware to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.89% chance of exploitation within 30 days, higher than 60% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update Vigor3912 Firmware to 4.3.6.1 or a later version.
  2. Update Vigor2962 Firmware to 4.3.2.8 or 4.4.3.1, whichever matches your release line, or a later version.
  3. Update Vigor3910 Firmware to 4.3.2.8 or 4.4.3.1, whichever matches your release line, 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
DraytekVigor3912 Firmwarebefore 4.3.6.14.3.6.1
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
DraytekVigor3910 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
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
DraytekVigor166 Firmwarebefore 4.2.74.2.7
DraytekVigor2135 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2763 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2765 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2865 Firmwarebefore 4.4.5.24.4.5.2
DraytekVigor2766 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2866 Firmwarebefore 4.4.5.24.4.5.2
DraytekVigor2915 Firmwarebefore 4.4.5.34.4.5.3
DraytekVigor2620 FirmwareNot specified in the recordNot stated
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 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
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.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalNVD
CVSS 3.19.8CriticalCISA (ADP)

Official description

DrayTek Vigor310 devices through 4.3.2.6 allow a remote attacker to execute arbitrary code via the function ft_payload_dns(), because a byte sign-extension operation occurs for the length argument of a _memcpy call, leading to a heap-based Buffer Overflow.

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

The underlying weakness: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended 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 Out-of-bounds Write vulnerabilities (CWE-787)

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

Patches and release notes

Other vulnerabilities in Vigor3912 Firmware

All Vigor3912 Firmware vulnerabilities

Recent Out-of-bounds Write vulnerabilities

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