CVE-2026-23239

Kernel memory corruption via ESP-in-TCP teardown race

Published Mar 10, 2026 · Updated Mar 10, 2026

A race condition in the Linux Kernel ESP-in-TCP implementation allows local users to trigger use-after-free memory access during socket teardown. espintcp_close() cancels pending work without preventing espintcp_write_space() or softirq paths from scheduling espintcp_tx_work(), which then dereferences a freed context or socket. Exploitation requires local low-privileged access and winning the teardown race; successful corruption compromises kernel confidentiality, integrity, and availability.

CVSS severity7.8
High
EPSS probability0.10%
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 the Linux Kernel ESP-in-TCP implementation allows local users to trigger use-after-free memory access during socket teardown. espintcp_close() cancels pending work without preventing espintcp_write_space() or softirq paths from scheduling espintcp_tx_work(), which then dereferences a freed context or socket. Exploitation requires local low-privileged access and winning the teardown race; successful corruption compromises kernel confidentiality, integrity, and availability.

The record

CVE
CVE-2026-23239
Published
Mar 10, 2026
Updated
Mar 10, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-362, CAPEC-26, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 10, 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=5.6
  2. Affected versionversion=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <022ff7f347588de6e17879a1da6019647b21321b
  3. Affected versionversion=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <664e9df53226b4505a0894817ecad2c610ab11d8
  4. Affected versionversion=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <e1512c1db9e8794d8d130addd2615ec27231d994
  5. Affected versionversion=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <f7ad8b1d0e421c524604d5076b73232093490d5c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.6; version=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <022ff7f347588de6e17879a1da6019647b21321b; version=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <664e9df53226b4505a0894817ecad2c610ab11d8; version=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <e1512c1db9e8794d8d130addd2615ec27231d994; version=e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 <f7ad8b1d0e421c524604d5076b73232093490d5c

Published CVSS scores

7.8Linux kernel CVE teamCVSS: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-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CAPEC-26Leveraging Race Conditions
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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