number of supported devices · tty: hvc_iucv: fix off-by-one
Affects MicrosoftSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 26 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Security Response Center Microsoft | Affected
| Fixed in– |
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.
References
- nvd.nist.gov/vuln/detail/CVE-2026-53306 (opens in a new tab)
- git.kernel.org/stable/c/11207e42a332eb8bbcb9fe74df9edd2a807c5607 (opens in a new tab)
- git.kernel.org/stable/c/3104a3f40feb107f77d7116ad9bf6c210ab7babf (opens in a new tab)
- git.kernel.org/stable/c/3d3b89e6ab93bdd0efd45828bda6b0e61cc46dff (opens in a new tab)
- git.kernel.org/stable/c/484357dff256c816d9466bda35eb765685e4dc86 (opens in a new tab)
- git.kernel.org/stable/c/a76511bc654819425d3b15e77b523d7f9d81f064 (opens in a new tab)
- git.kernel.org/stable/c/f1dc8e72de9aabe5d96767a4e97219ac26b79fe5 (opens in a new tab)
- git.kernel.org/stable/c/f2a880e802ad12d1e38039d1334fb1475d0f5241 (opens in a new tab)
- git.kernel.org/stable/c/fed8b8f33a46db0ee2efdb000f4f630c86ed8ca4 (opens in a new tab)