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Incorrect Permission AssignmentWeakness · CWE-732

CVE-2026-15779

MEDIUM · 6.1 CVSS v3.1 Published 2026-07-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
63/100
Remediation priority · Elevated
Zero-click 5 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

pam_winbind's mkhomedir functionality does not validate whether the target home directory path is a critical system directory before performing a chown operation. When accounts (such as system accounts) have '/' set as their home directory, a non-root user with sudo delegation to run commands as that account can trigger pam_winbind to change ownership of the root filesystem, causing catastrophic availability loss.

MitigationEnsure system accounts do not have '/' as their home directory; consider disabling mkhomedir for system accounts or applying any available samba updates that add path validation in pam_winbind.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify pam_winbind package is installed
    Check for pam_winbind in the package manager (e.g., dpkg -l | grep pam_winbind, rpm -qa | grep winbind, or ls /lib/security/pam_winbind.so)
    Affected if pam_winbind package is present on the system
  2. Identify if mkhomedir is enabled in PAM configuration
    Search PAM configuration files for 'pam_winbind.so mkhomedir' entry (e.g., grep -r 'pam_winbind.*mkhomedir' /etc/pam.d/)
    Affected if pam_winbind with mkhomedir directive is configured in any PAM service file
  3. Check for accounts with '/' as home directory
    Query accounts with home directory set to '/' using 'getent passwd' or 'awk -F: '$6=="/" {print}' /etc/passwd'
    Affected if Any account (especially system accounts like daemon, bin, sys) has '/' listed as the home directory field
  4. Review sudo permissions for non-root users
    Check for sudo rules allowing execution as accounts with '/' home directory (e.g., sudo -l -U target_user or examine /etc/sudoers and /etc/sudoers.d/)
    Affected if Non-root users have sudo privileges to run commands as accounts with '/' as home directory
  5. Confirm conjunction of conditions
    Cross-reference: if pam_winbind mkhomedir is active AND accounts with '/' home exist AND non-root users can sudo to those accounts, the system is vulnerable
    Affected if All three conditions (pam_winbind mkhomedir enabled, '/' home directory accounts present, sudo access to those accounts by non-root users) are true simultaneously

The environment is affected only if pam_winbind mkhomedir is enabled, system accounts with '/' as home directory exist, AND non-root users have sudo delegation to execute commands as those accounts, allowing chown of the root filesystem.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Ensure system accounts do not have '/' as their home directory; consider disabling mkhomedir for system accounts or applying any available samba updates that add path validation in pam_winbind.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-15779 in production — separate from our analysis above.

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