Description
A flaw was found in samba's pam_winbind. When mkhomedir is enabled, pam_winbind chowns the target account's home directory without validating the path is not a critical system directory such as /. On affected systems, accounts with / as their home directory (a common default for system accounts) can have this triggered not only by root, but by a non-root user holding a narrow sudo delegation to run commands as that account, causing ownership of / to change and resulting in severe denial of service (SSH, sudo, and package-manager failures). The change does not grant write access to / (which ships with restrictive 0555 permissions on RHEL), so the impact is availability loss rather than further privilege escalation.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Red Hat Red Hat Enterprise Linux 10
Default version status: affected
Red Hat Red Hat Enterprise Linux 6
Default version status: unknown
Red Hat Red Hat Enterprise Linux 7
Default version status: affected
Red Hat Red Hat Enterprise Linux 8
Default version status: affected
Red Hat Red Hat Enterprise Linux 9
Default version status: affected
References
- https://access.redhat.com/security/cve/CVE-2026-15779 ↗
- https://bugzilla.redhat.com/show_bug.cgi?id=2499991 ↗
- https://gitlab.com/samba-team/samba/-/blob/samba-4.19.4/nsswitch/pam_winbind.c ↗
- https://gitlab.com/samba-team/samba/-/blob/samba-4.23.5/nsswitch/pam_winbind.c#L1622 ↗
- https://gitlab.com/samba-team/samba/-/blob/samba-4.24.3/nsswitch/pam_winbind.c#L1590 ↗