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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| [UNKNOWN] | samba | 4.7.12, 4.8.7, 4.9.3 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | samba | 2:4.9.2+dfsg-2 | — |
| Debian 13 | samba | 2:4.9.2+dfsg-2 | — |
| Debian 12 | samba | 2:4.9.2+dfsg-2 | — |
| Debian 9 | samba | 2:4.5.12+dfsg-2+deb9u4 | DSA-4345-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | samba | 2:4.7.6+dfsg~ubuntu-0ubuntu2.5 | USN-3827-1 |
| Ubuntu 16.04 LTS | samba | 2:4.3.11+dfsg-0ubuntu0.16.04.18 | USN-3827-1 |
| Ubuntu 14.04 LTS | samba | 2:4.3.11+dfsg-0ubuntu0.14.04.19 | USN-3827-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 | samba | 4.7.11+git.140.6bd0e5b30d8-4.21.1 | SUSE-SU-2018:4066-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | samba | 4.14.6+git.182.2205d5224e3-1.1 | openSUSE-SU-2024:11365-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | samba | 4.8.7-r0 | — |
| Alpine v3.23 | samba | 4.8.7-r0 | — |
| Alpine v3.22 | samba | 4.8.7-r0 | — |
| Alpine v3.21 | samba | 4.8.7-r0 | — |
| Alpine v3.20 | samba | 4.8.7-r0 | — |
Show 14 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | samba | 4.8.7-r0 | — |
| Alpine v3.18 | samba | 4.8.7-r0 | — |
| Alpine v3.17 | samba | 4.8.7-r0 | — |
| Alpine v3.16 | samba | 4.8.7-r0 | — |
| Alpine v3.15 | samba | 4.8.7-r0 | — |
| Alpine v3.14 | samba | 4.8.7-r0 | — |
| Alpine v3.13 | samba | 4.8.7-r0 | — |
| Alpine v3.12 | samba | 4.8.7-r0 | — |
| Alpine v3.11 | samba | 4.8.7-r0 | — |
| Alpine v3.10 | samba | 4.8.7-r0 | — |
| Alpine v3.9 | samba | 4.8.7-r0 | — |
| Alpine v3.8 | samba | 4.8.8-r0 | — |
| Alpine v3.7 | samba | 4.7.6-r2 | — |
| Alpine v3.6 | samba | 4.6.16-r2 | — |
Advisories 4
- USN-3827-1 samba vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DSA-4345-1 samba - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:11365-1 ctdb-4.14.6+git.182.2205d5224e3-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:4066-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
References
- 106023 vdb-entry
- USN-3827-2 vendor-advisory
- USN-3827-1 vendor-advisory
- https://security.netapp.com/advisory/ntap-20181127-0001/
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16841
- DSA-4345 vendor-advisory
- https://www.samba.org/samba/security/CVE-2018-16841.html
- GLSA-202003-52 vendor-advisory