CVE-2023-53205

KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler

HIGH
7.8
CVSS Score
Published: September 15, 2025 at 02:21 PM UTC
Updated: October 15, 2026 at 10:17 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.8
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: s390/diag: fix racy access of physical cpu number in diag 9c handler We do check for target CPU == -1, but this might change at the time we are going to use it. Hold the physical target CPU in a local variable to avoid out-of-bound accesses to the cpu arrays.

Affected

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

5.13 ≤ v < 5.15.1215.16 ≤ v < 6.1.396.2 ≤ v < 6.4.45.1387e28a15c42cc592009c32a8c20e5789059027c2
Vendor states this is fixed in 0bc380beb78aa352eadbc21d934dd9606fcee808 (fixed)
Vendor states this is fixed in 86bfb18bad60fc468e5f112cbbd918462a8dd435 (fixed)
Vendor states this is fixed in a9ccf140a2a03a0ae82be4bdfbdd17bdaea72ff5 (fixed)
Vendor states this is fixed in dc7e0192c470a53d847c79a2796f9ac429477a26 (fixed)
Vendor states this is fixed in 5.13 (unaffected)
Vendor states this is fixed in 5.15.121 (unaffected)
Vendor states this is fixed in 6.1.39 (unaffected)
Vendor states this is fixed in 6.4.4 (unaffected)
Vendor states this is fixed in 6.5 (unaffected)

References (4)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/0bc380beb78aa352eadbc21d934dd9606fcee808
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/86bfb18bad60fc468e5f112cbbd918462a8dd435
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/a9ccf140a2a03a0ae82be4bdfbdd17bdaea72ff5
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/dc7e0192c470a53d847c79a2796f9ac429477a26

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-787

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