CVE-2026-81000

Last refreshed2026-10-17

Status: UPDATED | Advisory ID: CVE-2026-81000

Key Details

CVE	CVE-2026-81000
CVSS Score / Version	7.8 (High) / CVSS v3.1
Updated	2026-10-16
CVSS Vector	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`
CVSS Prose	attack vector is local; attack complexity is low; privileges required is low; user interaction is none; scope is unchanged; confidentiality impact is high; integrity impact is high; availability impact is high.
Affected products	Linux Kernel

Vendor	Product	Affected Versions	Patch Status
Linux	Linux Kernel

Vendor

Product

Affected Versions

Patch Status

Linux

Linux Kernel

Subsystems	OT Supporting Infrastructure
Sectors	All Sectors

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

net: tun: bound receive headroom

tun_get_user() uses tun->align both as skb headroom and when choosing how

much packet data to keep linear. OVS can propagate an oversized headroom

request from another port to TUN or TAP.

When align is larger than the usable space in a one-page skb head,

SKB_MAX_HEAD(align) underflows and the result becomes negative when stored

in good_linear. That value later wraps when assigned to the size_t linear

variable, and tun_alloc_skb() can place skb->data outside the allocated

head.

Bound the headroom stored by TUN to the one-page skb-head budget and the

largest non-sentinel 16-bit skb header offset. Leave one linear byte for

raw TUN and a complete Ethernet header for TAP, including NET_IP_ALIGN.

Also pull the raw-TUN protocol byte and the TAP Ethernet header before

accessing them, so these checks remain safe for nonlinear skbs supplied by

other allocation paths. (NVD)

Monitor Linux's web page for any future patch releases.

Source	Reference
NVD	https://nvd.nist.gov/vuln/detail/CVE-2026-81000
CVE	https://www.cve.org/CVERecord?id=CVE-2026-81000

Source

Reference

NVD

CVE