CVE-2026-75092 Leapp-repository: leapp-upgrade-el9toel10: leapp-upgrade-el9toel10: scan_mysql runs mysqld --validate-config as root and can load mysql-writable plugins

Description

A privilege escalation flaw was found in the scan_mysql actor of leapp-upgrade-el9toel10 (provided by leapp-repository). During RHEL 9 to RHEL 10 upgrades, the actor runs: mysqld --validate-config --log-error-verbosity=2 directly as root in the Leapp actor context, bypassing the packaged MySQL systemd unit that normally starts the daemon as User=mysql. A process compromised as the mysql OS identity can write a version-2 persisted configuration (mysqld-auto.cnf) and a malicious shared object into /var/lib/mysql (a directory owned by mysql). That persisted map can set plugin_dir to /var/lib/mysql and early_plugin_load (or related loader options such as plugin_load / plugin_load_add) so MySQL loads the attacker-controlled object during configuration validation. Plugin loading can reach dlopen() before MySQL’s runtime-user check and before plugin-symbol validation. When an administrator subsequently runs the documented Leapp preupgrade or upgrade workflow, attacker-controlled code can execute as UID 0 with a full capability set in an unconfined SELinux domain (unconfined_t). The attack does not require write access to the default system plugin path under /usr; redirecting plugin_dir via mysql-owned persisted state is sufficient. Ordinary SQL privileges alone (including highly privileged SQL accounts) are not a sufficient startpoint — OS-level execution as the mysql service identity is required, plus later administrator invocation of Leapp.

Exploitable with local access to the machine, with an ordinary account and if a user takes an action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector

Local

Attack complexity

Low

Privileges required

Low

Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected products and versions