Description
A flaw was found in Samba. The smbd service daemon does not pick up group membership changes when re-authenticating an expired SMB session. This issue can expose file shares until clients disconnect and then connect again.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | samba | 4.21.0 – < 4.21.6 | 4.21.6 |
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Enterprise Linux 6 | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Red Hat | Red Hat OpenShift Container Platform 4 | — | — |
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 | 2:4.22.2+dfsg-1 | — |
| Debian 13 | samba | 2:4.22.2+dfsg-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 25.04 | samba | 2:4.21.4+dfsg-1ubuntu3.1 | USN-7564-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | samba | 4.21.6+git.402.80f493f530f-150700.3.3.1 | SUSE-SU-2025:02230-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | samba | 4.22.2+git.396.c752843dcf4-1.1 | openSUSE-SU-2025:15296-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | samba | 4.21.6-r0 | — |
| Alpine v3.23 | samba | 4.21.6-r0 | — |
| Alpine v3.22 | samba | 4.21.6-r0 | — |
Advisories 4
- openSUSE-SU-2025:15296-1 ctdb-4.22.2+git.396.c752843dcf4-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2025:02230-1 Security update for samba SUSE / openSUSE Security Updates · Mar 23, 2026
- USN-7564-1 samba vulnerability Ubuntu Security Notices (USN) · Jan 14, 2026
- WID-SEC-2025-1221 Samba: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Nov 17, 2025