What’s Vulnerable › Vulnerabilities

CVE-2018-16841

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-11-28 · updated 2026-06-17
• Weakness: CWE-416

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.

Affected products

• Canonical Ubuntu Linux: 12.04, 14.04, 16.04, 18.04, 18.10
• Debian Linux: 9.0
• Samba: from 4.3.0 before 4.7.12; from 4.8.0 before 4.8.7; from 4.9.0 before 4.9.3 — fixed in 4.7.12, 4.8.7, 4.9.3

How to fix

Upgrade to a fixed version: Samba 4.7.12, 4.8.7, 4.9.3. Check the vendor advisory for mitigations.

References

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

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