CVE-2023-53376 scsi: mpi3mr: Use number of bits to manage bitmap sizes

What is CVE-2023-53376?

CVE-2023-53376 is a high-severity memory corruption vulnerability in Linux kernel, published on 18 Sep 2025. 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:

scsi: mpi3mr: Use number of bits to manage bitmap sizes

To allocate bitmaps, the mpi3mr driver calculates sizes of bitmaps using byte as unit. However, bitmap helper functions assume that bitmaps are allocated using unsigned long as unit. This gap causes memory access beyond the bitmap sizes and results in "BUG: KASAN: slab-out-of-bounds". The BUG was observed at firmware download to eHBA-9600. Call trace indicated that the out-of-bounds access happened in find_first_zero_bit() called from mpi3mr_send_event_ack() for miroc->evtack_cmds_bitmap.

To fix the BUG, do not use bytes to manage bitmap sizes. Instead, use number of bits, and call bitmap helper functions which take number of bits as arguments. For memory allocation, call bitmap_zalloc() instead of kzalloc() and krealloc(). For memory free, call bitmap_free() instead of kfree(). For zero clear, call bitmap_clear() instead of memset().

Remove three fields for bitmap byte sizes in struct scmd_priv which are no longer required. Replace the field dev_handle_bitmap_sz with dev_handle_bitmap_bits to keep number of bits of removepend_bitmap across resize.

Weakness: CWE-125

Which versions are affected by CVE-2023-53376?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2023-53376?

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-2023-53376 being exploited?

There is no known exploitation of CVE-2023-53376 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-72325, BELL-CVE-2023-53376, DEBIAN-CVE-2023-53376, GHSA-6f3q-hg2c-hwrx, ROOT-OS-UBUNTU-2204-CVE-2023-53376, UBUNTU-CVE-2023-53376.