CVE-2023-0459

Kernel-memory disclosure via missing speculation barrier

Published May 25, 2023 · Updated Sep 26, 2024

Information disclosure in 64-bit Linux Kernel usercopy functions allows local users to infer kernel memory through speculative execution. The copy_from_user path speculatively accepts a kernel address after access_ok is mispredicted and, without barrier_nospec, lets later cache effects encode copied data. Exploitation requires local code execution, a susceptible 64-bit processor, and a usable side channel; systems with SMAP enabled were not demonstrated exploitable.

CVSS severity6.5
Medium
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in 64-bit Linux Kernel usercopy functions allows local users to infer kernel memory through speculative execution. The copy_from_user path speculatively accepts a kernel address after access_ok is mispredicted and, without barrier_nospec, lets later cache effects encode copied data. Exploitation requires local code execution, a susceptible 64-bit processor, and a usable side channel; systems with SMAP enabled were not demonstrated exploitable.

The record

CVE
CVE-2023-0459
Published
May 25, 2023
Updated
Sep 26, 2024
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-763, T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 25, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 26, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4b842e4e25b12951fa10dedb4bc16bc47e3b850c <=74e19ef0ff8061ef55957c3abd71614ef0f42f47

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4b842e4e25b12951fa10dedb4bc16bc47e3b850c <=74e19ef0ff8061ef55957c3abd71614ef0f42f47

Published CVSS scores

6.5Google Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-763Release of Invalid Pointer or Reference
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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