CVE-2026-62430

x86: Out-of-bounds read in vRTC emulation

State
Published
Severity
7.5 High
Published
Jul 28, 2026
Updated
Jul 28, 2026
Reserved
Jul 14, 2026

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Description

Accesses to the CMOS memory contents are done using an indirect IO port pair. Therefore Xen needs to cache the guest chosen index, and one of the usages of the index didn't take the necessary locking to avoid concurrent changes. As a result, a guest could change the index after it being checked, causing a subsequent out-of-bound read access to the contents of an array.

Scores

CVSSScoreVectorSource
3.17.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NCISA-ADP

Weaknesses

  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Affected Products

ProductVersions
XenXen
  • consult Xen advisory XSA-503Unknown

References

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