CVE-2026-4408
Samba: remote code execution in samr
CRITICAL 9.8EPSS 1.8%
A flaw was found in Samba. A remote attacker can exploit a misconfiguration in Samba file servers and classic domain controllers that use the "check password script" feature. If this script is configured with the %u substitution character, the client-controlled username is passed without proper escaping of shell meta-characters. This vulnerability allows an attacker to achieve remote command execution on the affected system. This issue primarily affects non-standard configurations where the "check password script" is used with %u and the samba-dcerpcd service is started as a system service.
- Affected
- Red Hat · Red Hat Enterprise Linux 10 · Red Hat Enterprise Linux 10.0 Extended Update Support · Red Hat Enterprise Linux 7 Extended Lifecycle Support · Red Hat Enterprise Linux 8 · Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support · Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
- CVSS v3.1 NVD
- 9.8 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS v3.1 CNA
- 9.0 CRITICAL
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - EPSS
- 1.75% chance of exploitation in the next 30 days, 77th percentile
- Published
- 2026-05-28
- Updated
- 2026-10-08
Proof-of-concept exploits (1)
- SafeBreach-Labs/ForgottenButNotGone10★ · 2026-08-03
Security advisories
- https://bugzilla.samba.org/show_bug.cgi?id=16034
- https://access.redhat.com/security/cve/CVE-2026-4408
- https://bugzilla.redhat.com/show_bug.cgi?id=2479762
- https://access.redhat.com/errata/RHSA-2026:22644
- https://access.redhat.com/errata/RHSA-2026:22963