CVE-2026-75092
Vulnérabilité élevée dans Red Hat Enterprise Linux 9 (Red Hat)
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.
Gravité et risque d'exploitation
CVE-2026-75092 obtient un score CVSS de 7.3/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.13 %, ce qui la place devant 2.2 % des CVE référencées.
Que faire ?
- Vérifiez si Red Hat Enterprise Linux 9 (versions 0:0.22.0-1.el9_6.2, <*, 0:0.24.0-1.el9_8.1) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- https://access.redhat.com/errata/RHSA-2026:67608
- https://access.redhat.com/errata/RHSA-2026:67609
- https://access.redhat.com/security/cve/CVE-2026-75092
- https://bugzilla.redhat.com/show_bug.cgi?id=2517499
- https://github.com/oamg/leapp-repository
- https://github.com/oamg/leapp-repository/commit/3e4cafffc8de1600a66519b326a407f37b665356
- https://github.com/oamg/leapp-repository/pull/1343
