Samba Vulnerabilities — Ubuntu Security Update (USN-8621-1)
This is a security release for Ubuntu 20.04, Ubuntu 22.04. The fix ships in the current release line (referenced builds: 26.04, 24.04, 22.04, 23.6). Update the product on every affected server to the patched release — there is no workaround, and unpatched servers remain exposed until updated.
Fix Commands
Debian/Ubuntu
sudo apt update && sudo apt upgradeWhat this means under a SharedLicense license
Your SharedLicense license itself is not affected — this is a change in Ubuntu 20.04, Ubuntu 22.04 software, not in licensing. Update the product through its standard update channel. Licenses keep working through updates; nothing needs re-issuing or re-activating.
It was discovered that Samba’s pam_winbind incorrectly handled home
directory ownership when mkhomedir was enabled. A local attacker could
possibly use this issue to cause a denial of service by triggering a change
in ownership of the root directory. (CVE-2026-15779)
Arjun Basnet, Douglas Bagnall, and Andrew Tridge…
It was discovered that Samba’s pam_winbind incorrectly handled home
directory ownership when mkhomedir was enabled. A local attacker could
possibly use this issue to cause a denial of service by triggering a change
in ownership of the root directory. (CVE-2026-15779)
Arjun Basnet, Douglas Bagnall, and Andrew Tridge…
It was discovered that Samba’s pam_winbind incorrectly handled home
directory ownership when mkhomedir was enabled. A local attacker could
possibly use this issue to cause a denial of service by triggering a change
in ownership of the root directory. (CVE-2026-15779)
Arjun Basnet, Douglas Bagnall, and Andrew Tridge…
It was discovered that Samba’s pam_winbind incorrectly handled home
directory ownership when mkhomedir was enabled. A local attacker could
possibly use this issue to cause a denial of service by triggering a change
in ownership of the root directory. (CVE-2026-15779)
Arjun Basnet, Douglas Bagnall, and Andrew Tridge…
-
USN-8621-1
Publication date
28 July 2026
Overview
Several security issues were fixed in Samba.
Releases
Open side navigation
Packages
- samba – SMB/CIFS file, print, and login server for Unix
Details
It was discovered that Samba’s pam_winbind incorrectly handled home
directory ownership when mkhomedir was enabled. A local attacker could
possibly use this issue to cause a denial of service by triggering a change
in ownership of the root directory. (CVE-2026-15779)
Arjun Basnet, Douglas Bagnall, and Andrew Tridgell discovered that Samba
incorrectly handled TSIG packets with name compression. A remote attacker
could possibly use this issue to cause Samba to crash, resulting in a
denial of service. (CVE-2026-6949)
Tristan Madani discovered that Samba incorrectly handled malformed ASN.1
kpasswd packets. An authenticated user could possibly use this issue to
cause Samba to crash, resulting in a denial of service. (CVE-2026-58216)
Andrew Tridgell and Tristan Madani discovered that Samba incorrectly
handled TKEY…
It was discovered that Samba’s pam_winbind incorrectly handled home
directory ownership when mkhomedir was enabled. A local attacker could
possibly use this issue to cause a denial of service by triggering a change
in ownership of the root directory. (CVE-2026-15779)
Arjun Basnet, Douglas Bagnall, and Andrew Tridgell discovered that Samba
incorrectly handled TSIG packets with name compression. A remote attacker
could possibly use this issue to cause Samba to crash, resulting in a
denial of service. (CVE-2026-6949)
Tristan Madani discovered that Samba incorrectly handled malformed ASN.1
kpasswd packets. An authenticated user could possibly use this issue to
cause Samba to crash, resulting in a denial of service. (CVE-2026-58216)
Andrew Tridgell and Tristan Madani discovered that Samba incorrectly
handled TKEY name registration. A remote attacker could possibly use this
issue to exhaust the TKEY name cache, resulting in a denial of service.
(CVE-2026-58218)
It was discovered that Samba incorrectly handled internal LDB special
directory names when processing authenticated LDAP requests. An
authenticated user could possibly use this issue to perform unauthorized
modifications and gain control of a domain. (CVE-2026-58221)
Andrew Tridgell and Tristan Madani discovered that Samba incorrectly
handled LDAP Compare requests. An authenticated user could possibly use
this issue to obtain sensitive information. (CVE-2026-58222)
Tristan Madani, Andrew Tridgell, and Martin Schwenke discovered that the
CTDB protocol in Samba had insufficient bounds checking. A remote attacker
could possibly use this issue to cause Samba to crash, resulting in a
denial of service. (CVE-2026-58224)
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Update instructions
In general, a standard system update will make all the necessary changes.
Learn more about how to get the fixes.
The problem can be corrected by updating your system to the following package versions:
| Ubuntu Release | Package Version | ||
|---|---|---|---|
|
26.04
LTS resolute |
samba – | ||
|
24.04
LTS noble |
samba – | ||
|
22.04
LTS jammy |
samba – | ||
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References
References
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