CVE-2026-23032 null_blk: fix kmemleak by releasing references to fault configfs items
A memory leak in the Linux kernel null_blk driver allows local attackers to exhaust kernel memory, causing denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23032?
CVE-2026-23032 is a memory corruption vulnerability in Linux, published on 31 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
null_blk: fix kmemleak by releasing references to fault configfs items
When CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION is enabled, the null-blk driver sets up fault injection support by creating the timeout_inject, requeue_inject, and init_hctx_fault_inject configfs items as children of the top-level nullbX configfs group.
However, when the nullbX device is removed, the references taken to these fault-config configfs items are not released. As a result, kmemleak reports a memory leak, for example:
unreferenced object 0xc00000021ff25c40 (size 32): comm "mkdir", pid 10665, jiffies 4322121578 hex dump (first 32 bytes): 69 6e 69 74 5f 68 63 74 78 5f 66 61 75 6c 74 5f init_hctx_fault_ 69 6e 6a 65 63 74 00 88 00 00 00 00 00 00 00 00 inject.......... backtrace (crc 1a018c86): __kmalloc_node_track_caller_noprof+0x494/0xbd8 kvasprintf+0x74/0xf4 config_item_set_name+0xf0/0x104 config_group_init_type_name+0x48/0xfc fault_config_init+0x48/0xf0 0xc0080000180559e4 configfs_mkdir+0x304/0x814 vfs_mkdir+0x49c/0x604 do_mkdirat+0x314/0x3d0 sys_mkdir+0xa0/0xd8 system_call_exception+0x1b0/0x4f0 system_call_vectored_common+0x15c/0x2ec
Fix this by explicitly releasing the references to the fault-config configfs items when dropping the reference to the top-level nullbX configfs group.
Which versions are affected by CVE-2026-23032?
How do I fix CVE-2026-23032?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-23032 being exploited?
There is no known exploitation of CVE-2026-23032 in the wild and no public exploit code.
Sources
Also known as AZL-77214, BELL-CVE-2026-23032, DEBIAN-CVE-2026-23032, GHSA-jq2q-j87r-jrqv, ROOT-OS-UBUNTU-2404-CVE-2026-23032, UBUNTU-CVE-2026-23032.