Support Announcements
DIR-2640 / DIR-2640-US :: H/W Rev. Ax :: F/W v1.01B04 :: Stack Overflow & Write Out-of-Bounds in Server Process Security Vulnerabilities




On February 9, 2021, a 3rd party security research submitted a report accusing the DIR-2640/DIR-2640-US using firmware v1.01B04 of two vulnerabilites with one of the device's server process. The vulnerabilities were confirmed and a patch was issued too close the reported issues. 


Please find the beta/hotfix release below.

3rd Party Report information


          - Report provided:

                    li yansong  :: liyansong2012 _at_ outlook _dot_ com

          - Reference :

                   3rd Party Public Disclosure :: CVE-2021-34202

                       - The NL_ Server Process has a buffer stack overflow

                       - The NL_ Server process will allow write out of bounds


 Affected Models


Model Hardware Revision Affected FW Fixed FW Recommendation  Last Updated

DIR-2640 &


All Ax Hardware Revisions v1.01B04 & Below v1.11B02 Hotfix

1) Please Download Patch and Update Device

2) Full QA Firmware under test for automatic F/W update

notification on D-Link Wifi mobile App



Regarding Security patch for your D-Link Devices
Firmware updates address the security vulnerabilities in affected D-Link devices. D-Link will update this continually and we strongly recommend all users to install the relevant updates.
Please note that this is a device beta software, beta firmware, or hot-fix release which is still undergoing final testing before its official release. The beta software, beta firmware, or hot-fix is provided on an “as is” and “as available” basis and the user assumes all risk and liability for use thereof. D-Link does not provide any warranties, whether express or implied, as to the suitability or usability of the beta firmware. D-Link will not be liable for any loss, whether such loss is direct, indirect, special or consequential, suffered by any party as a result of their use of the beta firmware.
As there are different hardware revisions on our products, please check this on your device before downloading the correct corresponding firmware update. The hardware revision information can usually be found on the product label on the underside of the product next to the serial number. Alternatively, they can also be found on the device web configuration.