CVE-2023-39189

Kernel disclosure and crash via unchecked option count

Published Oct 9, 2023 · Updated Nov 6, 2025

An out-of-bounds read in the Linux kernel on Red Hat Enterprise Linux 8 and 9 allows local users with CAP_NET_ADMIN to disclose memory. nfnl_osf_add_callback accepts a user-controlled opt_num without checking it against the nf_osf_finger option-array length, so nf_osf_match_one reads beyond the array. Exploitation requires CAP_NET_ADMIN and can disclose kernel memory or crash the system.

CVSS severity5.1
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An out-of-bounds read in the Linux kernel on Red Hat Enterprise Linux 8 and 9 allows local users with CAP_NET_ADMIN to disclose memory. nfnl_osf_add_callback accepts a user-controlled opt_num without checking it against the nf_osf_finger option-array length, so nf_osf_match_one reads beyond the array. Exploitation requires CAP_NET_ADMIN and can disclose kernel memory or crash the system.

The record

CVE
CVE-2023-39189
Published
Oct 9, 2023
Updated
Nov 6, 2025
Vendor
Red Hat
Product
Red Hat Enterprise Linux 8
Classifications
CWE-125, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Oct 9, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 6, 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?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Red Hat · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.

Published CVSS scores

6.0NIST NVDCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H
5.1Red Hat, Inc.CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:L

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

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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