SB2026072141 - Out-of-bounds write in Linux kernel kvm svm



SB2026072141 - Out-of-bounds write in Linux kernel kvm svm

Published: July 21, 2026

Security Bulletin ID SB2026072141
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Out-of-bounds write (CVE-ID: CVE-2026-63794)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to cause memory corruption.

The vulnerability exists due to an out-of-bounds write in sev_dbg_crypt() when processing crafted KVM SEV debug encryption requests. A local user can send a crafted ioctl request with page offsets that cause the transfer length to exceed the destination page boundary to cause memory corruption.

The issue affects the encrypt path and can overflow a single-page intermediate buffer by up to 15 bytes when the destination offset is greater than the source offset.


Remediation

Install update from vendor's website.