CVE-2026-82593 is a stack-based buffer overflow in the LTE Module Firmware Upgrade component of the D-Link DIR-825M, a mass-market wireless router with an LTE fallback/upgrade path, sold through general electronics retailers, with no dependency on a specific fixed-line ISP.

The following version(s) are affected:

D-Link DIR-825M firmware 1.1.8 – (Affected)

No fixed firmware version currently available – (Not applicable)

Step 1 - Reach the device's LTE firmware-upgrade function

An attacker with low-level access to the router's web-management interface sends a crafted request to /boafrm/formLtefotaUpgradeFibocom with an oversized "fota_url" value.

Step 2 - Trigger the overflow and execute code

The oversized value overflows a stack buffer in the function sub_41802C, allowing the attacker to execute arbitrary code on the device or crash it outright, using the publicly documented exploit technique.

Attack vectors:

• A network-based attack against any reachable D-Link DIR-825M's web-management interface, requiring only low-level access to that interface (CVSS PR:L).
• No user interaction is required, and a public exploit already exists.

Successful exploitation may allow attackers to:

• Execute arbitrary code on the affected router, or crash it and disrupt the internet connectivity of any home, small office, or organization relying on it.
• Use a compromised router as a foothold to intercept, redirect, or manipulate the network traffic of every device connected behind it.

CERTVU recommends the following:

1. Restrict access to the device's web-management interface

   Disable remote/WAN-side administration and restrict access to the management interface to trusted local devices only; change any default or weak management credentials immediately.

2. Monitor for a vendor firmware update

3. Consider replacement if no patch is released

4. Segment consumer networking devices from sensitive systems

Report any suspected compromise of a D-Link DIR-825M device, or unusual network behaviour on a network using one, to CERTVU at This email address is being protected from spambots. You need JavaScript enabled to view it. or on telephone (678) 33380.