In the Linux kernel, the following vulnerability has been resolved: ext4: fix timer use-after-free on failed mount Syzbot has found an ODEBUG bug in ext4_fill_super The del_timer_sync function cancels the s_err_report timer, which reminds about filesystem errors daily. We should guarantee the timer is no longer active before kfree(sbi). When filesystem mounting fails, the flow goes to failed_mount3, where an error occurs when ext4_stop_mmpd is called, causing a read I/O failure. This triggers the ext4_handle_error function that ultimately re-arms the timer, leaving the s_err_report timer active before kfree(sbi) is called. Fix the issue by canceling the s_err_report timer after calling ext4_stop_mmpd.
Upstream advisory: https://lore.kernel.org/linux-cve-announce/2024102131-CVE-2024-49960-f9cb@gregkh/T
This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2025:6966 https://access.redhat.com/errata/RHSA-2025:6966