D-Link Systems has identified a critical security vulnerability in its DIR-822A router, which has been assigned the entity code CVE-2026-86296. It arises from the use of the unsafe strcpy function to copy attacker-controlled data into a fixed-size stack buffer, leading to a stack-based buffer overflow. If the crafted input exceeds the available buffer space, it can overwrite adjacent memory, leading to device crashes, service disruptions, or even allow an attacker to execute unauthorized code on the router.
This issue is classified under Stack-Based Buffer Overflow (S-BUG) and Improper Restriction of Operations within the Bounds of a Memory Buffer (IROBMB). The published CVSS vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R. Exploitation could compromise confidentiality, integrity, and availability, making the vulnerability particularly significant for routers connected directly to the public internet.
Organizations using the affected router should treat the issue as a high-priority exposure-management concern, even while D-Link continues its validation efforts. Users should refrain from exposing router administration interfaces to the internet, disable remote management when it’s not necessary, and restrict administrative access to trusted systems. D-Link reminded users that firmware is hardware-revision specific, meaning installing an image intended for a different revision could damage the device or leave it unsecured.
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