Out-of-bounds Read Affecting kernel-zfcpdump-modules-core package, versions *
Threat Intelligence
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Test your applications- Snyk IDSNYK-RHEL10-KERNELZFCPDUMPMODULESCORE-21741948
- published27 Oct 2026
- disclosed23 Oct 2026
Introduced: 23 Oct 2026
NewCVE-2026-99063 (opens in a new tab)How to fix?
There is no fixed version for RHEL:10 kernel-zfcpdump-modules-core.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-zfcpdump-modules-core package and not the kernel-zfcpdump-modules-core package as distributed by RHEL.
See How to fix? for RHEL:10 relevant fixed versions and status.
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.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=2559788
- https://access.redhat.com/security/cve/CVE-2026-99063
- https://git.kernel.org/stable/c/5680b6fb3054677d4ee65d3baba24b649f1b430e
- https://git.kernel.org/stable/c/725b49c689bbb29ef740b0d6b5ea9390baa9a695
- https://git.kernel.org/stable/c/98195e822343a656b92e235847ab3e72b1a3f920
- https://git.kernel.org/stable/c/9b3fcf519d370df94a56f3b272d9eddffffa5be8
- https://git.kernel.org/stable/c/e5c3f3d8935ecc64c962fb66e6a86dbf79218f61