Description
A flaw was found in Samba's internal DNS server where unauthenticated TKEY registration requests were added to the TKEY name cache before being rejected. A remote, unauthenticated attacker can exploit this behavior by sending a large number of TKEY requests with arbitrary names, exhausting the cache and evicting legitimate TKEY entries. This can prevent legitimate TSIG authentication for signed DNS queries, resulting in a denial of service.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| 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 | 2:4.24.5+dfsg-1 | — |
| Debian 13 | samba | 2:4.22.10+dfsg-0+deb13u2 | — |
| Debian 12 | samba | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | samba | 2:4.23.6+dfsg-1ubuntu2.2 | — |
| Ubuntu 24.04 LTS | samba | 2:4.19.5+dfsg-4ubuntu9.7 | — |
| Ubuntu 22.04 LTS | samba | 2:4.15.13+dfsg-0ubuntu1.13 | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | samba | No fix yet | — |
| Ubuntu Pro 18.04 LTS | samba | No fix yet | — |
| Ubuntu Pro 16.04 LTS | samba | No fix yet | — |
| Ubuntu Pro 14.04 LTS | samba | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | samba | 4.21.10+git.533.31d7e5508d-150700.3.29.1 | SUSE-SU-2026:3363-1 |
| SLES 15 SP6 | samba | 4.19.8+git.501.67274891bc-150600.3.29.1 | SUSE-SU-2026:3364-1 |
| SLES 15 SP5 | samba | 4.17.12+git.581.f49579c6cd-150500.3.42.1 | SUSE-SU-2026:3365-1 |
| SLES 15 SP4 | samba | 4.15.13+git.808.eeca19f5e1-150400.3.52.1 | SUSE-SU-2026:3362-1 |
| SLES 12 SP5 | samba | 4.15.13+git.729.a8ce057e8d-3.109.1 | SUSE-SU-2026:3367-1 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | samba | 4.22.11+git.552.66cfeb7de0a-160000.1.1 | SUSE-SU-2026:23152-1, SUSE-SU-2026:23129-1 |
| SLES for SAP 15 SP6 | samba | 4.19.8+git.501.67274891bc-150600.3.29.1 | SUSE-SU-2026:3364-1 |
| SLES for SAP 15 SP5 | samba | 4.17.12+git.581.f49579c6cd-150500.3.42.1 | SUSE-SU-2026:3365-1 |
| SLES for SAP 15 SP4 | samba | 4.15.13+git.808.eeca19f5e1-150400.3.52.1 | SUSE-SU-2026:3362-1 |
| SLES 16.0 | samba | 4.22.11+git.552.66cfeb7de0a-160000.1.1 | SUSE-SU-2026:23152-1, SUSE-SU-2026:23129-1 |
| SLE Micro 6.2 | samba | 4.22.9+git.538.af6cb4fb2e-160000.1.1 | SUSE-SU-2026:23003-1, SUSE-SU-2026:22977-1 |
| SLE Micro 5.5 | samba | 4.17.12+git.581.f49579c6cd-150500.3.42.1 | SUSE-SU-2026:3365-1 |
| SLE Micro 5.4 | samba | 4.15.13+git.808.eeca19f5e1-150400.3.52.1 | SUSE-SU-2026:3362-1 |
| SLE Micro 5.3 | samba | 4.15.13+git.808.eeca19f5e1-150400.3.52.1 | SUSE-SU-2026:3362-1 |
| SLE HPC 15 SP5 | samba | 4.17.12+git.581.f49579c6cd-150500.3.42.1 | SUSE-SU-2026:3365-1 |
| SLE HPC 15 SP4 | samba | 4.15.13+git.808.eeca19f5e1-150400.3.52.1 | SUSE-SU-2026:3362-1 |
| SUSE Enterprise Storage 7.1 | samba | 4.15.13+git.808.eeca19f5e1-150300.3.106.1 | SUSE-SU-2026:3366-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | samba | 4.24.5+git.481.dba78dbdea-1.1 | openSUSE-SU-2026:11431-1 |
| openSUSE Leap 16.0 | samba | 4.22.9+git.538.af6cb4fb2e-160000.1.1 | openSUSE-SU-2026:21540-1, openSUSE-SU-2026:21475-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | samba +31 | 2:4.17.12-1.amzn2023.0.7 | ALAS2023-2026-2135 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | samba | No fix yet | — |
Advisories 15
- WID-SEC-2026-2549 Samba: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 20, 2026
- ALAS2023-2026-2135 Important: samba security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 14, 2026
- SUSE-SU-2026:23152-1 Security update for samba SUSE / openSUSE Security Updates · Aug 14, 2026
- SUSE-SU-2026:23129-1 Security update for samba SUSE / openSUSE Security Updates · Aug 14, 2026
- SUSE-SU-2026:23003-1 Security update for samba SUSE / openSUSE Security Updates · Aug 12, 2026
- openSUSE-SU-2026:21540-1 Security update for samba SUSE / openSUSE Security Updates · Aug 8, 2026
- SUSE-SU-2026:22977-1 Security update for samba SUSE / openSUSE Security Updates · Aug 4, 2026
- openSUSE-SU-2026:11431-1 ctdb-4.24.5+git.481.dba78dbdea-1.1 on GA media SUSE / openSUSE Security Updates · Aug 2, 2026
- openSUSE-SU-2026:21475-1 Security update for samba SUSE / openSUSE Security Updates · Jul 31, 2026
- SUSE-SU-2026:3364-1 Security update for samba SUSE / openSUSE Security Updates · Jul 29, 2026
- SUSE-SU-2026:3365-1 Security update for samba SUSE / openSUSE Security Updates · Jul 29, 2026
- SUSE-SU-2026:3366-1 Security update for samba SUSE / openSUSE Security Updates · Jul 29, 2026
- SUSE-SU-2026:3367-1 Security update for samba SUSE / openSUSE Security Updates · Jul 29, 2026
- SUSE-SU-2026:3362-1 Security update for samba SUSE / openSUSE Security Updates · Jul 29, 2026
- SUSE-SU-2026:3363-1 Security update for samba SUSE / openSUSE Security Updates · Jul 29, 2026