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.
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 |
| Debian 8 | samba | 2:4.2.14+dfsg-0+deb8u11 | DLA-1607-1 |
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 5
- 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
- DLA-1607-1 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
- 106027 vdb-entry
- USN-3827-2 vendor-advisory
- USN-3827-1 vendor-advisory
- https://security.netapp.com/advisory/ntap-20181127-0001/
- [debian-lts-announce] 20181215 [SECURITY] [DLA 1607-1] samba security update mailing-list
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16851
- DSA-4345 vendor-advisory
- https://www.samba.org/samba/security/CVE-2018-16851.html
- GLSA-202003-52 vendor-advisory