CVE-2023-54139

Local privilege escalation via negative write index

Published Dec 24, 2025 · Updated Dec 24, 2025

Out-of-bounds access in the Linux kernel user_events subsystem allows local users to gain kernel privileges via a negative write index. user_events_write_core treats the first four write bytes as a signed index but checks only whether it is below the array count, letting negative values index before the per-file event array. Exploitation requires local write access to tracefs user_events_data; the resulting bogus event-pointer dereference can disclose or corrupt kernel memory or panic the system.

CVSS severity7.8
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in the Linux kernel user_events subsystem allows local users to gain kernel privileges via a negative write index. user_events_write_core treats the first four write bytes as a signed index but checks only whether it is below the array count, letting negative values index before the per-file event array. Exploitation requires local write access to tracefs user_events_data; the resulting bogus event-pointer dereference can disclose or corrupt kernel memory or panic the system.

The record

CVE
CVE-2023-54139
Published
Dec 24, 2025
Updated
Dec 24, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 24, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 24, 2025Record 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=5.18
  2. Affected versionversion=7f5a08c79df35e68f1a43033450c5050f12bc155 <0489c2b2c3104b89f078dbcec8c744dfc157d3e9
  3. Affected versionversion=7f5a08c79df35e68f1a43033450c5050f12bc155 <4fe46b5adf18e3dc606e62c9e6a0413398a17572
  4. Affected versionversion=7f5a08c79df35e68f1a43033450c5050f12bc155 <cd98c93286a30cc4588dfd02453bec63c2f4acf4
  5. Affected versionversion=7f5a08c79df35e68f1a43033450c5050f12bc155 <fa7f2f5d1739452280c22727c4384a52b72ab5de

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.18; version=7f5a08c79df35e68f1a43033450c5050f12bc155 <0489c2b2c3104b89f078dbcec8c744dfc157d3e9; version=7f5a08c79df35e68f1a43033450c5050f12bc155 <4fe46b5adf18e3dc606e62c9e6a0413398a17572; version=7f5a08c79df35e68f1a43033450c5050f12bc155 <cd98c93286a30cc4588dfd02453bec63c2f4acf4; version=7f5a08c79df35e68f1a43033450c5050f12bc155 <fa7f2f5d1739452280c22727c4384a52b72ab5de

Published CVSS scores

7.8Linux CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.

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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

T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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