D-Link DIR-825M Stack-Based Buffer Overflow via LTE FOTA Upgrade Handler
First seen Sep 1, 2026 · Updated Sep 1, 2026 · CVSS 9.9
A critical remote code execution vulnerability exists in D-Link DIR-825M 1.1.8 routers, caused by a stack-based buffer overflow in the LTE Module Firmware Upgrade handler (formLtefotaUpgradeFibocom). An attacker can remotely manipulate the fota_url parameter to trigger the overflow, with a public exploit already available, making this an immediate risk to exposed devices.
Technical Analysis
The vulnerability resides in the function sub_41802C within the /boafrm/formLtefotaUpgradeFibocom endpoint of the DIR-825M's BOA-based web management interface, part of the LTE Module Firmware Upgrade component. Insufficient bounds checking on the fota_url argument allows an attacker to overflow a stack buffer, potentially enabling arbitrary code execution on the device with a CVSS score of 9.9, indicating minimal complexity and no privileges required for remote exploitation. Because the exploit code is publicly available, attackers can rapidly weaponize this flaw for botnet recruitment, traffic interception, or lateral network pivoting. Organizations deploying AI agent infrastructure behind or through affected D-Link routers face indirect risk: a compromised router can be used to intercept, redirect, or manipulate network traffic between agents and their LLM APIs, tool endpoints, or RAG data sources, potentially exposing API keys or poisoning agent inputs.
Affected Systems
D-Link DIR-825M router, firmware version 1.1.8, specifically the LTE Module Firmware Upgrade component and its formLtefotaUpgradeFibocom endpoint
Indicators of Compromise
- Endpoint: /boafrm/formLtefotaUpgradeFibocom
- Parameter: fota_url
- Function: sub_41802C
Remediation Steps
- 1
Apply Vendor Patch
Check D-Link's security advisories for a firmware update addressing CVE-2026-82593 and apply it immediately once available.
- 2
Restrict Remote Management
Disable remote/WAN access to the router's web administration interface and restrict management access to trusted LAN segments only.
- 3
Network Segmentation
Isolate IoT and network infrastructure devices from segments hosting AI agent workloads, API keys, or sensitive data pipelines.
- 4
Deploy Compensating Controls
Use a firewall or IPS to block or monitor traffic to the vulnerable formLtefotaUpgradeFibocom endpoint until a patch is applied.
- 5
Device Replacement Planning
If the device is end-of-life and unpatched, plan replacement with a supported router model as a longer-term mitigation.
CVE / Advisory IDs
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