CIFS-UTILS PrivEsc via request_key and malicious NSS Module
CVE-2026-12505 Published on June 18, 2026
Cifs-utils: local privilege escalation via forged cifs.spnego key description in cifs.upcall
A flaw was found in the cifs-utils package where the cifs.upcall helper fails to securely drop its root privileges before looking up user information inside a user-controlled environment. A local, low privileged attacker can exploit this by using a crafted request_key payload to trick the root-owned helper into entering a custom environment (namespace) containing a malicious NSS module. This forces the system to load the attacker's controlled NSS Module and configuration, allowing them to execute arbitrary commands as the root user, elevating their privileges and fully compromising the system.
Vulnerability Analysis
CVE-2026-12505 can be exploited with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Timeline
Reported to Red Hat.
Made public.
Weakness Type
Execution with Unnecessary Privileges
The software performs an operation at a privilege level that is higher than the minimum level required, which creates new weaknesses or amplifies the consequences of other weaknesses.
Products Associated with CVE-2026-12505
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