Answer in brief
CVE-2026-99063 records a Unknown severity vulnerability in dm ioctl: don't let data_start run past the buffer. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=76c072b48e39e9291fbf02d6c912cf27d65e093d <98195e822343a656b92e235847ab3e72b1a3f920 || >=76c072b48e39e9291fbf02d6c912cf27d65e093d <e5c3f3d8935ecc64c962fb66e6a86dbf79218f61 || >=76c072b48e39e9291fbf02d6c912cf27d65e093d <5680b6fb3054677d4ee65d3baba24b649f1b430e || >=76c072b48e39e9291fbf02d6c912cf27d65e093d <725b49c689bbb29ef740b0d6b5ea9390baa9a695 || >=76c072b48e39e9291fbf02d6c912cf27d65e093d <9b3fcf519d370df94a56f3b272d9eddffffa5be8 | 98195e822343a656b92e235847ab3e72b1a3f920, e5c3f3d8935ecc64c962fb66e6a86dbf79218f61, 5680b6fb3054677d4ee65d3baba24b649f1b430e, 725b49c689bbb29ef740b0d6b5ea9390baa9a695, 9b3fcf519d370df94a56f3b272d9eddffffa5be8 |
| Linux/Linuxgeneric | 2.6.25 | Not reported |
Published upstream
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 23, 2026
In the Linux kernel, the following vulnerability has been resolved: dm ioctl: don't let data_start run past the buffer struct dm_ioctl has seven bytes of trailing padding, so the smallest buffer userspace is allowed to ask for, offsetof(struct dm_ioctl, data), is seven bytes shorter than sizeof(struct dm_ioctl). get_result_buffer() sets data_start to sizeof(struct dm_ioctl) without looking at how big the buffer actually is. Ask for the minimum and data_start ends up seven bytes past the end. Callers add it to data_size, and ctl_ioctl() copies that much back to userspace: BUG: KASAN: slab-out-of-bounds in _copy_to_user+0xad/0xd0 Read of size 312 at addr ffff8880169e4c00 by task repro-dm/140 ctl_ioctl+0x5e3/0xcb0 dm_ctl_ioctl+0x25/0x40 allocated 305-byte region [ffff8880169e4c00, ffff8880169e4d31) A DM_LIST_DEVICES with data_size set to 305 is enough to hit it, and the seven bytes that leak are whatever sat next to the allocation. Clamp data_start to the buffer size. Note that this is not a security bug because the out-of-bounds read can only be triggered by root.
Quoted source text, attributed separately from HOL analysis.