CVE-2026-15779 Samba-winbind: samba: pam_winbind mkhomedir chowns critical system paths without validation
Attackers with limited sudo access can trigger pam_winbind to change ownership of the root directory, causing severe system denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-15779?
CVE-2026-15779 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, published on 15 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-732
Which versions are affected by CVE-2026-15779?
How do I fix CVE-2026-15779?
Apply the vendor's patch.
Is CVE-2026-15779 being exploited?
There is no known exploitation of CVE-2026-15779 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-15779, ECHO-9793-9b10-71e9, GHSA-6fmw-7w5g-3pf9, OESA-2026-3364, OESA-2026-3365, OESA-2026-3410 and 3 more.