5.5

CVE-2026-53306: tty: hvc_iucv: fix off-by-one in number of supported devices

Analyzed
AliasesUBUNTU-CVE-2026-53306DEBIAN-CVE-2026-53306
Published 26-06-2026Last modified 26-06-2026

Vulnerability summary

CVE-2026-53306 is a medium (CVSS 5.5) Off-by-one Error vulnerability in linux. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 5.4% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.16%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 49 · Related 49
OPENSUSE-SU-2026:21388-1SUSE-SU-2026:22742-1SUSE-SU-2026:22769-1SUSE-SU-2026:22809-1SUSE-SU-2026:22810-1SUSE-SU-2026:22812-1

Timeline

  1. 26-06-2026
    PublishedVulnerability first disclosed.

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.16%

Chance of exploitation in the next 30 days

Percentile

5%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.16% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu166 products
  • linuxAll versions (No fix recorded) | < 5.15.0-186.196 | < 6.8.0-136.136 | < 7.0.0-28.28
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1112.119 | < 6.8.0-1061.64 | < 7.0.0-1009.9
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 44a01d5ba8a4d543694461cd3e178cfa6b3f221b, < 3d3b89e6ab93bdd0efd45828bda6b0e61cc46dff | ≥ 44a01d5ba8a4d543694461cd3e178cfa6b3f221b, < 484357dff256c816d9466bda35eb765685e4dc86 | ≥ 44a01d5ba8a4d543694461cd3e178cfa6b3f221b, < 11207e42a332eb8bbcb9fe74df9edd2a807c5607 | ≥ 44a01d5ba8a4d543694461cd3e178cfa6b3f221b, < fed8b8f33a46db0ee2efdb000f4f630c86ed8ca4 | ≥ 44a01d5ba8a4d543694461cd3e178cfa6b3f221b, < a76511bc654819425d3b15e77b523d7f9d81f064 | ≥ 44a01d5ba8a4d543694461cd3e178cfa6b3f221b, < 3104a3f40feb107f77d7116ad9bf6c210ab7babf | ≥ 44a01d5ba8a4d543694461cd3e178cfa6b3f221b, < f1dc8e72de9aabe5d96767a4e97219ac26b79fe5 | ≥ 44a01d5ba8a4d543694461cd3e178cfa6b3f221b, < f2a880e802ad12d1e38039d1334fb1475d0f5241 | 2.6.29
  • linux_kernel≥ 2.6.29, < 5.10.258 | ≥ 5.11, < 5.15.209 | ≥ 5.16, < 6.1.175 | ≥ 6.2, < 6.6.141 | ≥ 6.7, < 6.12.91 | ≥ 6.13, < 6.18.33 | ≥ 6.19, < 7.0.10
Debian1 product
  • linux< 6.1.176-1 | < 6.12.94-1 | < 7.0.10-1

3 vendors · 169 products

References

49 links
Show all 49 references