CVE-2023-52633

Instance crash via timer adjustment race

Published Apr 2, 2024 · Updated May 11, 2026

A race condition in Linux UML time handling allows local users to crash a User Mode Linux instance during basic time-travel operation. In timer_read, an interrupt can update time_travel_time after a forward adjustment is calculated but before it is applied, causing the stale adjustment to move time backward. The crash requires low local privileges, user interaction, and basic mode without inf-cpu or ext; the host kernel remains running.

CVSS severity5.0
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race condition in Linux UML time handling allows local users to crash a User Mode Linux instance during basic time-travel operation. In timer_read, an interrupt can update time_travel_time after a forward adjustment is calculated but before it is applied, causing the stale adjustment to move time backward. The crash requires low local privileges, user interaction, and basic mode without inf-cpu or ext; the host kernel remains running.

The record

CVE
CVE-2023-52633
Published
Apr 2, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 2, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record 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=065038706f77a56754e8f0c2556dab7e22dfe577 <0c7478a2da3f5fe106b4658338873d50c86ac7ab
  2. Affected versionversion=065038706f77a56754e8f0c2556dab7e22dfe577 <4f7dad73df4cdb2b7042103d3922745d040ad025
  3. Affected versionversion=065038706f77a56754e8f0c2556dab7e22dfe577 <abe4eaa8618bb36c2b33e9cdde0499296a23448c
  4. Affected versionversion=065038706f77a56754e8f0c2556dab7e22dfe577 <b427f55e9d4185f6f17cc1e3296eb8d0c4425283
  5. Affected versionversion=065038706f77a56754e8f0c2556dab7e22dfe577 <de3e9d8e8d1ae0a4d301109d1ec140796901306c
  6. Affected versionversion=5.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=065038706f77a56754e8f0c2556dab7e22dfe577 <0c7478a2da3f5fe106b4658338873d50c86ac7ab; version=065038706f77a56754e8f0c2556dab7e22dfe577 <4f7dad73df4cdb2b7042103d3922745d040ad025; version=065038706f77a56754e8f0c2556dab7e22dfe577 <abe4eaa8618bb36c2b33e9cdde0499296a23448c; version=065038706f77a56754e8f0c2556dab7e22dfe577 <b427f55e9d4185f6f17cc1e3296eb8d0c4425283; version=065038706f77a56754e8f0c2556dab7e22dfe577 <de3e9d8e8d1ae0a4d301109d1ec140796901306c; version=5.3

Published CVSS scores

5.0NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H

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-787Out-of-bounds Write
T1499.004Application or System Exploitation

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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