What is CVE-2018-16841?

CVE-2018-16841 is a medium-severity vulnerability in Samba, classified under Use After Free. CVSS score: 6.5/10. Published 2018-11-28.

How severe is CVE-2018-16841?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Is CVE-2018-16841 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Use After Free in Samba

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. 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.

Vulnerability class: Use-After-Free

Published 2018-11-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.046 (91.3th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 91st percentile — 91.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.046 · newest: 0.046 · change: 0.000

Affected products

Samba
[Unknown] Samba — versions 4.9.3, 4.8.7, 4.7.12
Canonical Ubuntu Linux — versions 12.04, 14.04, 16.04
Debian Linux — versions 9.0

Weakness classification (CWE)

Public proof-of-concept exploits

ARPSyndicate/cve-scores

References

www.securityfocus.com/bid/106023 (VDB Entry, Third Party Advisory, vdb-entry)
usn.ubuntu.com/3827-2/ (vendor-advisory, Third Party Advisory)
usn.ubuntu.com/3827-1/ (vendor-advisory, Third Party Advisory)
security.netapp.com/advisory/ntap-20181127-0001/ (Third Party Advisory)
bugzilla.redhat.com/show_bug.cgi (Third Party Advisory, Issue Tracking)
www.debian.org/security/2018/dsa-4345 (vendor-advisory, Third Party Advisory)
www.samba.org/samba/security/CVE-2018-16841.html (Patch, Vendor Advisory)
security.gentoo.org/glsa/202003-52 (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2018-16841?: CVE-2018-16841 is a medium-severity vulnerability in Samba, classified under Use After Free. CVSS score: 6.5/10. Published 2018-11-28.
How severe is CVE-2018-16841?: Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2018-16841 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.