CVE-2022-50673 ext4: fix use-after-free in ext4_orphan_cleanup
A use-after-free vulnerability in the Linux kernel's ext4 filesystem allows attackers to cause a denial of service or potentially execute code during mount operations.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2022-50673?
CVE-2022-50673 is a high-severity use after free vulnerability in Linux, published on 9 Dec 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ext4: fix use-after-free in ext4_orphan_cleanup
I caught a issue as follows: ================================================================== BUG: KASAN: use-after-free in __list_add_valid+0x28/0x1a0 Read of size 8 at addr ffff88814b13f378 by task mount/710
CPU: 1 PID: 710 Comm: mount Not tainted 6.1.0-rc3-next #370 Call Trace: <TASK> dump_stack_lvl+0x73/0x9f print_report+0x25d/0x759 kasan_report+0xc0/0x120 __asan_load8+0x99/0x140 __list_add_valid+0x28/0x1a0 ext4_orphan_cleanup+0x564/0x9d0 [ext4] __ext4_fill_super+0x48e2/0x5300 [ext4] ext4_fill_super+0x19f/0x3a0 [ext4] get_tree_bdev+0x27b/0x450 ext4_get_tree+0x19/0x30 [ext4] vfs_get_tree+0x49/0x150 path_mount+0xaae/0x1350 do_mount+0xe2/0x110 __x64_sys_mount+0xf0/0x190 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK> [...] ==================================================================
Above issue may happen as follows: ------------------------------------- ext4_fill_super ext4_orphan_cleanup --- loop1: assume last_orphan is 12 --- list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan) ext4_truncate --> return 0 ext4_inode_attach_jinode --> return -ENOMEM iput(inode) --> free inode<12> --- loop2: last_orphan is still 12 --- list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan); // use inode<12> and trigger UAF
To solve this issue, we need to propagate the return value of ext4_inode_attach_jinode() appropriately.
Which versions are affected by CVE-2022-50673?
How do I fix CVE-2022-50673?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2022-50673 being exploited?
There is no known exploitation of CVE-2022-50673 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2022-50673, GHSA-8h9v-mf84-vh83, UBUNTU-CVE-2022-50673.