---
id: CVE-2026-53306
title: 'tty: hvc_iucv: fix off-by-one in number of supported devices'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  tty: hvc_iucv: fix off-by-one in number of supported devices

  MAX_HVC_IUCV_LINES == HVC_ALLOC_TTY_ADAPTERS == 8.
  This is the number of entries in:
    static struct hvc_i…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b <
    3d3b89e6ab93bdd0efd45828bda6b0e61cc46dff
  - >-
    Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b <
    484357dff256c816d9466bda35eb765685e4dc86
  - >-
    Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b <
    11207e42a332eb8bbcb9fe74df9edd2a807c5607
  - >-
    Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b <
    fed8b8f33a46db0ee2efdb000f4f630c86ed8ca4
  - >-
    Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b <
    a76511bc654819425d3b15e77b523d7f9d81f064
  - >-
    Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b <
    3104a3f40feb107f77d7116ad9bf6c210ab7babf
  - >-
    Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b <
    f1dc8e72de9aabe5d96767a4e97219ac26b79fe5
  - >-
    Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b <
    f2a880e802ad12d1e38039d1334fb1475d0f5241
  - Linux 2.6.29
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:26:13.374243Z'
published: '2026-06-26'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:34:19.674Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-53306'
references:
  - url: 'https://git.kernel.org/stable/c/3d3b89e6ab93bdd0efd45828bda6b0e61cc46dff'
  - url: 'https://git.kernel.org/stable/c/484357dff256c816d9466bda35eb765685e4dc86'
  - url: 'https://git.kernel.org/stable/c/11207e42a332eb8bbcb9fe74df9edd2a807c5607'
  - url: 'https://git.kernel.org/stable/c/fed8b8f33a46db0ee2efdb000f4f630c86ed8ca4'
  - url: 'https://git.kernel.org/stable/c/a76511bc654819425d3b15e77b523d7f9d81f064'
  - url: 'https://git.kernel.org/stable/c/3104a3f40feb107f77d7116ad9bf6c210ab7babf'
  - url: 'https://git.kernel.org/stable/c/f1dc8e72de9aabe5d96767a4e97219ac26b79fe5'
  - url: 'https://git.kernel.org/stable/c/f2a880e802ad12d1e38039d1334fb1475d0f5241'
tags:
  - cve.org
epss: 0.00162
epssPercentile: 0.05467
ingestedAt: '2026-11-06T16:57:43.250Z'
---

## Overview

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

tty: hvc_iucv: fix off-by-one in number of supported devices

MAX_HVC_IUCV_LINES == HVC_ALLOC_TTY_ADAPTERS == 8.
This is the number of entries in:
  static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];

Sometimes hvc_iucv_table[] is limited by:
(a)	if (num > hvc_iucv_devices) // for error detection
or
(b)	for (i = 0; i < hvc_iucv_devices; i++) // in 2 places
(so these 2 don't agree; second one appears to be correct to me.)

hvc_iucv_devices can be 0..8. This is a counter.
(c)	if (hvc_iucv_devices > MAX_HVC_IUCV_LINES)

If hvc_iucv_devices == 8, (a) allows the code to access hvc_iucv_table[8].
Oops.

## Affected

- `Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b < 3d3b89e6ab93bdd0efd45828bda6b0e61cc46dff`
- `Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b < 484357dff256c816d9466bda35eb765685e4dc86`
- `Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b < 11207e42a332eb8bbcb9fe74df9edd2a807c5607`
- `Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b < fed8b8f33a46db0ee2efdb000f4f630c86ed8ca4`
- `Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b < a76511bc654819425d3b15e77b523d7f9d81f064`
- `Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b < 3104a3f40feb107f77d7116ad9bf6c210ab7babf`
- `Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b < f1dc8e72de9aabe5d96767a4e97219ac26b79fe5`
- `Linux >= 44a01d5ba8a4d543694461cd3e178cfa6b3f221b < f2a880e802ad12d1e38039d1334fb1475d0f5241`
- `Linux 2.6.29`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.