Description
A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | samba | samba 4.14.1, samba 4.13.6, samba 4.12.13 | — |
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 | 2:4.13.5+dfsg-2 | — |
| Debian 13 | samba | 2:4.13.5+dfsg-2 | — |
| Debian 12 | samba | 2:4.13.5+dfsg-2 | — |
| Debian 9 | samba | 2:4.5.16+dfsg-1+deb9u4 | DLA-2668-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | samba | 2:4.11.6+dfsg-0ubuntu1.8 | USN-4930-1 |
| Ubuntu 18.04 LTS | samba | 2:4.7.6+dfsg~ubuntu-0ubuntu2.23 | USN-4930-1 |
| Ubuntu 16.04 LTS | samba | 2:4.3.11+dfsg-0ubuntu0.16.04.34 | USN-4930-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 14.04 LTS | samba | 2:4.3.11+dfsg-0ubuntu0.14.04.20+esm11 | USN-4931-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | ctdb +24 | 4.13.3-5.el8_4 | RHSA-2021:4058 |
| RHEL 7 | ctdb +26 | 4.10.16-15.el7_9 | RHSA-2021:2313 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.2 EUS | ctdb +22 | 4.11.2-15.el8_2 | RHSA-2021:4866 |
| RHEL 7.7 TUS | samba +24 | 4.9.1-11.el7_7 | RHSA-2021:3988 |
| RHEL 7.7 E4S | samba +23 | 4.9.1-11.el7_7 | RHSA-2021:3988 |
| RHEL 7.7 AUS | samba +24 | 4.9.1-11.el7_7 | RHSA-2021:3988 |
| Red Hat Gluster Storage 3 | ctdb +20 | 4.11.6-112.el7rhgs | RHSA-2021:3724, RHSA-2021:3723 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | samba-devel +2 | 4.13.3-5.el8_4 | ALSA-2021:4058 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | samba | 4.13.3-5.el8_4 | RLSA-2021:4058 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | samba | 4.13.6+git.211.555d60b24ba-3.7.1 | SUSE-SU-2021:3187-1 |
| SLES 15 SP2 | samba | 4.11.14+git.247.8c858f7ee14-4.19.1 | SUSE-SU-2021:1444-1 |
| SLES 15 SP1 | samba | 4.9.5+git.432.d9b18c4f390-3.50.1 | SUSE-SU-2021:1498-1 |
| SLES 15 | samba | 4.7.11+git.316.432f0218290-4.54.1 | SUSE-SU-2021:1445-1 |
| SLES 12 SP5 | samba | 4.10.18+git.269.dd608524c88-3.27.1 | SUSE-SU-2021:1438-1 |
Show 23 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP4 | samba | 4.6.16+git.282.cfafed5922a-3.61.1 | SUSE-SU-2021:1492-1 |
| SLES 12 SP3 | samba | 4.6.16+git.282.cfafed5922a-3.61.1 | SUSE-SU-2021:1492-1 |
| SLES 12 SP2 | samba | 4.2.4-28.39.1 | SUSE-SU-2021:1442-1, SUSE-SU-2021:1439-1 |
| SLES 11 SP4 | samba +1 | 3.6.3-94.34.1 | SUSE-SU-2021:14709-1 |
| SLES 2 | samba | 4.11.14+git.247.8c858f7ee14-4.19.1 | SUSE-SU-2021:3187-1, SUSE-SU-2021:1444-1 |
| SLES for SAP 15 SP1 | samba | 4.9.5+git.432.d9b18c4f390-3.50.1 | SUSE-SU-2021:1498-1 |
| SLES for SAP 15 | samba | 4.7.11+git.316.432f0218290-4.54.1 | SUSE-SU-2021:1445-1 |
| SLES for SAP 12 SP5 | samba | 4.10.18+git.269.dd608524c88-3.27.1 | SUSE-SU-2021:1438-1 |
| SLES for SAP 12 SP4 | samba | 4.6.16+git.282.cfafed5922a-3.61.1 | SUSE-SU-2021:1492-1 |
| SLES for SAP 12 SP3 | samba | 4.6.16+git.282.cfafed5922a-3.61.1 | SUSE-SU-2021:1492-1 |
| SLE HPC 15 SP1 | samba | 4.9.5+git.432.d9b18c4f390-3.50.1 | SUSE-SU-2021:1498-1 |
| SLE HPC 15 | samba | 4.7.11+git.316.432f0218290-4.54.1 | SUSE-SU-2021:1445-1 |
| SUSE OpenStack Cloud Crowbar 9 | samba | 4.6.16+git.282.cfafed5922a-3.61.1 | SUSE-SU-2021:1492-1 |
| SUSE OpenStack Cloud Crowbar 8 | samba | 4.6.16+git.282.cfafed5922a-3.61.1 | SUSE-SU-2021:1492-1 |
| SUSE OpenStack Cloud 9 | samba | 4.6.16+git.282.cfafed5922a-3.61.1 | SUSE-SU-2021:1492-1 |
| SUSE OpenStack Cloud 8 | samba | 4.6.16+git.282.cfafed5922a-3.61.1 | SUSE-SU-2021:1492-1 |
| SUSE Manager Server 4.0 | samba | 4.9.5+git.432.d9b18c4f390-3.50.1 | SUSE-SU-2021:1498-1 |
| SUSE Manager Retail Branch Server 4.0 | samba | 4.9.5+git.432.d9b18c4f390-3.50.1 | SUSE-SU-2021:1498-1 |
| SUSE Manager Proxy 4.0 | samba | 4.9.5+git.432.d9b18c4f390-3.50.1 | SUSE-SU-2021:1498-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | samba +1 | 3.6.3-94.34.1 | SUSE-SU-2021:14709-1 |
| SUSE HPE Helion OpenStack 8 | samba | 4.6.16+git.282.cfafed5922a-3.61.1 | SUSE-SU-2021:1492-1 |
| SUSE Enterprise Storage 7 | ldb | 2.2.1-4.3.1 | SUSE-SU-2022:0361-1, SUSE-SU-2021:1440-1 |
| SUSE Enterprise Storage 7 | samba | 4.13.6+git.211.555d60b24ba-3.9.1 | SUSE-SU-2022:0361-1, SUSE-SU-2021:1440-1 |
| SUSE Enterprise Storage 6 | samba | 4.9.5+git.432.d9b18c4f390-3.50.1 | SUSE-SU-2021:1498-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | samba | 4.14.6+git.182.2205d5224e3-1.1 | openSUSE-SU-2024:11365-1 |
| openSUSE Leap 15.3 | samba | 4.13.6+git.211.555d60b24ba-3.7.1 | openSUSE-SU-2021:3187-1 |
| openSUSE Leap 15.2 | samba | 4.11.14+git.247.8c858f7ee14-lp152.3.19.1 | openSUSE-SU-2021:0636-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | samba | 4.14.4-r0 | — |
| Alpine v3.23 | samba | 4.14.4-r0 | — |
| Alpine v3.22 | samba | 4.14.4-r0 | — |
| Alpine v3.21 | samba | 4.14.4-r0 | — |
| Alpine v3.20 | samba | 4.14.4-r0 | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | samba | 4.14.4-r0 | — |
| Alpine v3.18 | samba | 4.14.4-r0 | — |
| Alpine v3.17 | samba | 4.14.4-r0 | — |
| Alpine v3.16 | samba | 4.14.4-r0 | — |
| Alpine v3.15 | samba | 4.14.4-r0 | — |
| Alpine v3.14 | samba | 4.14.4-r0 | — |
| Alpine v3.13 | samba | 4.13.8-r0 | — |
| Alpine v3.12 | samba | 4.12.15-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | ctdb +26 | 4.10.16-15.amzn2.0.1 | ALAS2-2021-1680 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | samba | 4.18.3-1 | — |
| Azure Linux 2 (CBL-Mariner) | samba | No fix yet | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | ctdb +24 | 4.13.3-5.el8_4 | ELSA-2021-4058 |
| Oracle Linux 7 | ctdb +26 | 4.10.16-15.el7_9 | ELSA-2021-2313 |
Advisories 30
- ALSA-2021:4058 Moderate: samba security update AlmaLinux Security Advisories · Oct 29, 2026
- USN-4931-1 samba vulnerabilities Ubuntu Security Notices (USN) · Jun 29, 2026
- RHSA-2021:3988 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2021:2313 Red Hat Security Advisory: samba security and bug fix update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2021:4866 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- RHSA-2021:4058 Red Hat Security Advisory: samba security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-4930-1 samba vulnerability Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-2668-1 samba - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RHSA-2021:3723 Red Hat Security Advisory: samba security, bug fix and enhancement update Red Hat Security Advisories (RHSA) · Feb 24, 2026
- RLSA-2021:4058 Moderate: samba security update Rocky Linux Security Advisories · Feb 5, 2026
- SUSE-SU-2021:1444-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 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-2021:1445-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:14709-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1440-1 Security update for ldb, samba SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0636-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1492-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1438-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1442-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1439-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:3187-1 Security update for samba SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:0361-1 Security update for ldb, samba SUSE / openSUSE Security Updates · Feb 4, 2026
- RHSA-2021:3724 Red Hat Security Advisory: samba security, bug fix and enhancement update Red Hat Security Advisories (RHSA) · Nov 22, 2025
- WID-SEC-2023-0063 Juniper Junos Space: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 8, 2025
- openSUSE-SU-2021:3187-1 Security update for samba SUSE / openSUSE Security Updates · May 7, 2025
- SUSE-SU-2021:1498-1 Security update for samba SUSE / openSUSE Security Updates · May 2, 2025
- WID-SEC-2023-2980 Samba: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Nov 21, 2023
- ELSA-2021-4058 Moderate: samba security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 2, 2021
- ALAS2-2021-1680 Moderate: samba security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jul 1, 2021
- ELSA-2021-2313 Moderate: samba security and bug fix update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Jun 9, 2021
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1949442
- https://www.samba.org/samba/security/CVE-2021-20254.html
- https://security.netapp.com/advisory/ntap-20210430-0001/
- FEDORA-2021-1d0807008b vendor-advisory
- FEDORA-2021-7026246ea9 vendor-advisory
- GLSA-202105-22 vendor-advisory
- [debian-lts-announce] 20210529 [SECURITY] [DLA 2668-1] samba security update mailing-list