CVE-2026-23458

Kernel memory access via stale conntrack pointer

Published Apr 3, 2026 · Updated Apr 3, 2026

Use-after-free in affected Linux Kernel releases allows local users to access freed kernel memory via a multi-round ctnetlink dump. ctnetlink_dump_exp_ct stores a conntrack pointer in cb->data but releases its reference before later dump callbacks dereference ct->ext through nfct_help. Low local privileges and a dump spanning multiple recvmsg rounds are required; published testing demonstrates an invalid kernel read, not reliable privilege escalation.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in affected Linux Kernel releases allows local users to access freed kernel memory via a multi-round ctnetlink dump. ctnetlink_dump_exp_ct stores a conntrack pointer in cb->data but releases its reference before later dump callbacks dereference ct->ext through nfct_help. Low local privileges and a dump spanning multiple recvmsg rounds are required; published testing demonstrates an invalid kernel read, not reliable privilege escalation.

The record

CVE
CVE-2026-23458
Published
Apr 3, 2026
Updated
Apr 3, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=3.10
  2. Affected versionversion=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <04c8907ce4e3d3e26c5e1a3e47aa5d17082cbb56
  3. Affected versionversion=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <5cb81eeda909dbb2def209dd10636b51549a3f8a
  4. Affected versionversion=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <bdf2724eefd4455a66863abb025bab8d3aa98c57
  5. Affected versionversion=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <cd541f15b60e2257441398cf495d978f816d09f8
  6. Affected versionversion=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <f025171feef2ac65663d7986f1d5ff0c28d6b2a9
  7. Affected versionversion=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <f04cc86d59906513d2d62183b882966fc0ae0390

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.10; version=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <04c8907ce4e3d3e26c5e1a3e47aa5d17082cbb56; version=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <5cb81eeda909dbb2def209dd10636b51549a3f8a; version=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <bdf2724eefd4455a66863abb025bab8d3aa98c57; version=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <cd541f15b60e2257441398cf495d978f816d09f8; version=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <f025171feef2ac65663d7986f1d5ff0c28d6b2a9; version=e844a928431fa8f1359d1f4f2cef53d9b446bf52 <f04cc86d59906513d2d62183b882966fc0ae0390

Published CVSS scores

7.8LinuxCVSS: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

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

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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