---
id: "CVE-2026-99097"
kind: "vulnerability"
aliases: ["CVE-2026-99097"]
title: "Linux kernel: zero-sized TEE shared memory allocation crashes the kernel"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "linux-kernel", "self-hosted", "tee"]
not_affected_if: ["default-config", "no-tee-driver"]
published_at: "2026-10-26T15:16:48+00:00"
first_seen_at: "2026-10-26T16:02:26+00:00"
updated_at: "2026-10-26T16:04:03+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99097", "first_seen_at": "2026-10-26T16:02:26+00:00"}]
---

# Linux kernel: zero-sized TEE shared memory allocation crashes the kernel

A zero-size request to the TEE shared memory ioctl (TEE_IOC_SHM_ALLOC) makes the kernel's page allocator hit a warning and fail the allocation. On kernels set to panic on warnings, this halts the machine.

_Summary, check and fix written by a model from the sources; labelled as such._

## Timeline

- 2026-10-26T16:02:26+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-99097

## From the sources

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

tee: shm: reject zero-sized allocations in tee_dyn_shm_alloc_helper()

tee_dyn_shm_alloc_helper() derives nr_pages from a caller-supplied size
and passes it to alloc_pages_exact() without checking it. For size == 0
nr_pages is 0, and alloc_pages_exact(0) calls get_order(0), which is
documented as undefined and returns BITS_PER_LONG - PAGE_SHIFT. The page
allocator then trips its order > MAX_PAGE_ORDER warning and fails the
allocation; on a panic_on_warn kernel that ends the boot.

This can be triggered by TEE_IOC_SHM_ALLOC with struct
tee_ioctl_shm_alloc_data where size is 0.

Reject a zero page count, as register_shm_helper() already does for the
register path.

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