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.
CVE-2026-15779
MEDIUMPre-NVD 6.16.1
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 6.1 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: cna:redhat
6.1
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: —CVSS: 6.1Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.1
- EG Score
- 6.1(low)
- EPSS
- —
- KEV
- Not listed
Published
July 15, 2026
Last Modified
July 15, 2026
Advisory Details (5)
Auto-updated Jul 15, 2026Patch available. Sources: redhat.
generic
nsswitch/pam_winbind.c · samba-4.24.3 · The Samba Team / Samba · GitLab
https://gitlab.com/samba-team/samba/-/blob/samba-4.24.3/nsswitch/pam_winbind.c#L1590generic
nsswitch/pam_winbind.c · samba-4.23.5 · The Samba Team / Samba · GitLab
https://gitlab.com/samba-team/samba/-/blob/samba-4.23.5/nsswitch/pam_winbind.c#L1622generic
nsswitch/pam_winbind.c · samba-4.19.4 · The Samba Team / Samba · GitLab
https://gitlab.com/samba-team/samba/-/blob/samba-4.19.4/nsswitch/pam_winbind.credhat Patch Available
2499991 – (CVE-2026-15779) CVE-2026-15779 samba-winbind: samba: pam_winbind mkhomedir chowns critical system paths without validation
https://bugzilla.redhat.com/show_bug.cgi?id=2499991Vendor Advisories for CVE-2026-15779(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 2× in last 7d / 2× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-15 12:54 UTCEG score recompute
- 2026-07-15 12:54 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-732
Frequently asked(4)
What is CVE-2026-15779?
CVE-2026-15779 is a medium vulnerability published on July 15, 2026. A flaw was found in samba's pamwinbind. When mkhomedir is enabled, pamwinbind 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…
When was CVE-2026-15779 disclosed?
CVE-2026-15779 was first published in the National Vulnerability Database on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-15779?
CVE-2026-15779 has a CVSS v3 base score of 6.1 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-15779?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-15779, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-15779
Is Your Infrastructure Affected by CVE-2026-15779?
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