CVE-2026-53306

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

MEDIUM

5.5

CVSS Score

Published: June 26, 2026 at 07:41 PM UTC

Updated: July 6, 2026 at 08:33 PM UTC

1 product affected across 1 vendorLinux Kernel

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Severity

MEDIUM5.5

Exploit prediction

EPSS 0.2%

Description

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel · Linux

95%

2.6.29 ≤ v < 5.10.2582.6.29 ≤ v < 5.15.2092.6.29 ≤ v < 6.1.1752.6.29 ≤ v < 6.12.912.6.29 ≤ v < 6.18.332.6.29 ≤ v < 6.6.1412.6.29 ≤ v < 7.0.102.6.29 ≤ v < 7.15.11 ≤ v < 5.15.2095.16 ≤ v < 6.1.1756.13 ≤ v < 6.18.336.19 ≤ v < 7.0.106.2 ≤ v < 6.6.1416.7 ≤ v < 6.12.912.6.2944a01d5ba8a4d543694461cd3e178cfa6b3f221b

Vendor states this is fixed in 11207e42a332eb8bbcb9fe74df9edd2a807c5607 (fixed)

Vendor states this is fixed in 3104a3f40feb107f77d7116ad9bf6c210ab7babf (fixed)

Vendor states this is fixed in 3d3b89e6ab93bdd0efd45828bda6b0e61cc46dff (fixed)

Vendor states this is fixed in 484357dff256c816d9466bda35eb765685e4dc86 (fixed)

Vendor states this is fixed in a76511bc654819425d3b15e77b523d7f9d81f064 (fixed)

Vendor states this is fixed in f1dc8e72de9aabe5d96767a4e97219ac26b79fe5 (fixed)

Vendor states this is fixed in f2a880e802ad12d1e38039d1334fb1475d0f5241 (fixed)

Vendor states this is fixed in fed8b8f33a46db0ee2efdb000f4f630c86ed8ca4 (fixed)

Vendor states this is fixed in 2.6.29 (unaffected)

Vendor states this is fixed in 5.10.258 (unaffected)

Vendor states this is fixed in 5.15.209 (unaffected)

Vendor states this is fixed in 6.1.175 (unaffected)