# CVE-2026-94089: D-Link DIR-868L stack-based buffer overflow in authentication handler

Source: https://junglewise.ai/threats/cve-2026-94089-a-vulnerability-was-determined-in-d-link-dir-868l-2-01b05-this  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-20. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-94089 · Severity: critical · CVSS 10 · Published 2026-09-20

A stack-based buffer overflow vulnerability exists in the D-Link DIR-868L wireless router's web authentication handler that can be exploited remotely without authentication. An attacker can send a specially crafted request with an oversized user ID parameter to crash the router's web server or potentially execute arbitrary code, leading to complete device compromise or denial of service.

Vendors: [D-Link](https://junglewise.ai/threats/vendors/d-link).

## Quick answers

**Is CVE-2026-94089 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-94089 being exploited in the wild.

**How severe is CVE-2026-94089?** Critical severity, with a CVSS score of 10, published 20 September 2026.

**Which products and versions are affected?** D-Link DIR-868L 2.01b05.

**Is there a fix for CVE-2026-94089?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-94089 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-94089?** Check whether you run D-Link DIR-868L at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a classic stack-based buffer overflow in the strcpy function within the /webfa_authentication.cgi authentication handler component. An unauthenticated remote attacker can manipulate the "id" URL parameter with a 1864-byte value to overflow the stack buffer, overwriting the saved return address and achieving return-address control. The PoC demonstrates that 1860 filler bytes plus a 4-byte marker triggers a crash at the function epilogue, confirming control of the instruction pointer.

## Affected products

- D-Link DIR-868L 2.01b05

## Timeline

- 2026-09-20: disclosed: Vulnerability publicly disclosed with proof-of-concept exploit
- 2026-09-20: advisory: CVE-2026-94089 assigned

## References

- [https://github.com/Walnut1337/CVE/blob/main/poc/poc_crash.py](https://github.com/Walnut1337/CVE/blob/main/poc/poc_crash.py)
- [https://vuldb.com/cve/CVE-2026-94089](https://vuldb.com/cve/CVE-2026-94089)