# CVE-2026-124560: D-Link DIR-878 heap buffer overflow in HNAP Handler

Source: https://junglewise.ai/threats/cve-2026-124560-a-vulnerability-was-found-in-d-link-dir-878-1-20b05-this-affects  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-09. Updated: 2026-11-09  
License: CC BY 4.0 with a link back

CVE-2026-124560 · Severity: critical · CVSS 9.8 · Published 2026-11-09

The D-Link DIR-878 wireless router contains a heap buffer overflow vulnerability in its HNAP configuration handler. An attacker can exploit this remotely by manipulating parameters sent to the router's web interface, potentially gaining control of the device, intercepting network traffic, or launching attacks on connected devices. The vulnerability affects end-of-life routers that no longer receive security updates.

Technologies: [D-Link DIR-878](https://junglewise.ai/threats/technologies/d-link-dir-878). Vendors: [D-Link](https://junglewise.ai/threats/vendors/d-link).

## Quick answers

**Is CVE-2026-124560 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-124560 being exploited in the wild.

**How severe is CVE-2026-124560?** Critical severity, with a CVSS score of 9.8, published 9 November 2026.

**Which products and versions are affected?** D-Link DIR-878 1.20B05.

**Is there a fix for CVE-2026-124560?** No fixed version is recorded yet. Do not expose the router to untrusted networks; restrict administrative access via firewall rules and disable remote management features if not required. However, since this product is end-of-life, replacement with a supported device is strongly recommended. 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-2026-124560 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-124560?** Check whether you run D-Link DIR-878 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.

## How to fix


Do not expose the router to untrusted networks; restrict administrative access via firewall rules and disable remote management features if not required. However, since this product is end-of-life, replacement with a supported device is strongly recommended.

## Technical details

A heap-based buffer overflow exists in the GetCAPTCHAsetting function within bin/prog.cgi when processing the uid argument via the HNAP Handler. The vulnerability is reachable remotely without authentication and can be exploited to achieve arbitrary code execution. Public exploit code is available, though no active wild exploitation has been reported yet.

## Affected products

- D-Link DIR-878 1.20B05

## Timeline

- 2026-11-09: disclosed

## References

- [https://github.com/Zimo-666/DIR-878-cves/tree/main/01-captcha-uid-heap-overflow](https://github.com/Zimo-666/DIR-878-cves/tree/main/01-captcha-uid-heap-overflow)
- [https://vuldb.com/cve/CVE-2026-124560](https://vuldb.com/cve/CVE-2026-124560)

## Related threats

- [D-Link DIR-878 path traversal in HNAP handler](https://junglewise.ai/threats/cve-2026-124564-a-weakness-has-been-identified-in-d-link-dir-878-1-20b05)
- [D-Link DIR-878 buffer overflow in HNAP SetWanSettings handler](https://junglewise.ai/threats/cve-2026-124563-a-security-flaw-has-been-discovered-in-d-link-dir-878-1-20b05)
- [D-Link DIR-878 buffer overflow in HNAP SetWanSettings](https://junglewise.ai/threats/cve-2026-124562-a-vulnerability-was-identified-in-d-link-dir-878-1-20b05)
- [D-Link DIR-878 stack buffer overflow in HNAP handler](https://junglewise.ai/threats/cve-2026-124561-a-vulnerability-was-determined-in-d-link-dir-878-1-20b05-this)