# CVE-2026-89515

## Summary

- **CVE ID:** CVE-2026-89515
- **Severity:** UNKNOWN
- **CVSS Score:** 0
- **CWE:** N/A
- **Published:** Sep 11, 2026
- **Last Modified:** Sep 16, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:

scsi: core: Fill in DMA padding bytes in scsi_alloc_sgtables()

During fuzz testing, the following issue was discovered:

BUG: KMSAN: uninit-value in __dma_map_sg_attrs+0x217/0x310
 __dma_map_sg_attrs+0x217/0x310
 dma_map_sg_attrs+0x4a/0x70
 ata_qc_issue+0x9f8/0x1420
 __ata_scsi_queuecmd+0x1657/0x1740
 ata_scsi_queuecmd+0x79a/0x920
 scsi_queue_rq+0x4472/0x4f40
 blk_mq_dispatch_rq_list+0x1cca/0x3ee0
 __blk_mq_sched_dispatch_requests+0x458/0x630
 blk_mq_sched_dispatch_requests+0x15b/0x340
 __blk_mq_run_hw_queue+0xe5/0x250
 __blk_mq_delay_run_hw_queue+0x138/0x780
 blk_mq_run_hw_queue+0x4bb/0x7e0
 blk_mq_sched_insert_request+0x2a7/0x4c0
 blk_execute_rq+0x497/0x8a0
 sg_io+0xbe0/0xe20
 scsi_ioctl+0x2b36/0x3c60
 sr_block_ioctl+0x319/0x440
 blkdev_ioctl+0x80f/0xd70
 __se_sys_ioctl+0x219/0x420
 __x64_sys_ioctl+0x93/0xe0
 x64_sys_call+0x1d6c/0x3ad0
 do_syscall_64+0x4c/0xa0
 entry_SYSCALL_64_after_hwframe+0x6e/0xd8

Uninit was created at:
 __alloc_pages+0x5c0/0xc80
 alloc_pages+0xe0e/0x1050
 blk_rq_map_user_iov+0x2b77/0x6100
 blk_rq_map_user_io+0x2fa/0x4d0
 sg_io+0xad6/0xe20
 scsi_ioctl+0x2b36/0x3c60
 sr_block_ioctl+0x319/0x440
 blkdev_ioctl+0x80f/0xd70
 __se_sys_ioctl+0x219/0x420
 __x64_sys_ioctl+0x93/0xe0
 x64_sys_call+0x1d6c/0x3ad0
 do_syscall_64+0x4c/0xa0
 entry_SYSCALL_64_after_hwframe+0x6e/0xd8

Bytes 14-15 of 16 are uninitialized
Memory access of size 16 starts at ffff88800cbdb000

When processing the last unaligned element of the scatterlist, it is
supplemented with missing bytes in the amount of pad_len.  These bytes
remain uninitialized, which leads to a problem.

Extend last_sg->length by pad_len first, then use sg_zero_buffer() to
zero those pad_len bytes.  sg_zero_buffer() uses sg_miter internally,
which correctly handles sg entries spanning multiple pages and padding
that crosses a page boundary.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

## Affected Products

- Linux — Linux (40b01b9bbdf51ae543a04744283bf2d56c4a6afa)
- Linux — Linux (2.6.25)
- Linux — Linux (0)
- Linux — Linux (6.12.109)
- Linux — Linux (6.18.50)
- Linux — Linux (7.2.4)
- Linux — Linux (7.3-rc1)
- Linux — Linux (5.10.270)
- Linux — Linux (5.15.221)
- Linux — Linux (6.1.188)
- Linux — Linux (6.6.157)

## References

- [CNA](https://git.kernel.org/stable/c/a4353ec7742bdf87dcdde5875270feb3a1982a51)
- [CNA](https://git.kernel.org/stable/c/e7143c3f4e5c0a7986733c6f27009274bf6c4264)
- [CNA](https://git.kernel.org/stable/c/6fd1cce5018fdcc8d928e00a6a1dd2997d5b9409)
- [CNA](https://git.kernel.org/stable/c/626147717bea776b61ed3631d2c26283760c4cc4)
- [CNA](https://git.kernel.org/stable/c/1aa6df61cef1f47f503c3ccf60d08c4dd931fdc1)
- [CNA](https://git.kernel.org/stable/c/6da140ebdfdd6aa3773945f2c0ebba01d2ef33d8)
- [CNA](https://git.kernel.org/stable/c/fd2cbe08c6ccba7fc1ddb830653a93bb7e2d833c)
- [CNA](https://git.kernel.org/stable/c/28ed5343666ff424ce5e248fa1c5a402303b4aff)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.18%
- **EPSS Percentile:** 7.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._