Linux Kernel up to 6.12.74/6.18.15/6.19.5/7.0-rc1 Delayed ACK espintcp_close race condition

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6.1$0-$5k0.00

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.12.74/6.18.15/6.19.5/7.0-rc1. This affects the function espintcp_close of the component Delayed ACK Handler. Performing a manipulation results in race condition. This vulnerability is known as CVE-2026-23239. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.12.74/6.18.15/6.19.5/7.0-rc1. This affects the function espintcp_close of the component Delayed ACK Handler. The manipulation with an unknown input leads to a race condition vulnerability. CWE is classifying the issue as CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: espintcp: Fix race condition in espintcp_close() This issue was discovered during a code audit. After cancel_work_sync() is called from espintcp_close(), espintcp_tx_work() can still be scheduled from paths such as the Delayed ACK handler or ksoftirqd. As a result, the espintcp_tx_work() worker may dereference a freed espintcp ctx or sk. The following is a simple race scenario: cpu0 cpu1 espintcp_close() cancel_work_sync(&ctx->work); espintcp_write_space() schedule_work(&ctx->work); To prevent this race condition, cancel_work_sync() is replaced with disable_work_sync().

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-23239 since 01/13/2026. The exploitability is told to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 301785 (Linux Distros Unpatched Vulnerability : CVE-2026-23239), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.75, 6.18.16, 6.19.6 or 7.0-rc2 eliminates this vulnerability. Applying the patch f7ad8b1d0e421c524604d5076b73232093490d5c/664e9df53226b4505a0894817ecad2c610ab11d8/e1512c1db9e8794d8d130addd2615ec27231d994 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (301785) and CERT Bund (WID-SEC-2026-0680). Be aware that VulDB is the high quality source for vulnerability data.

Affected

  • Open Source Linux Kernel

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.2
VulDB Meta Temp Score: 6.1

VulDB Base Score: 4.6
VulDB Temp Score: 4.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (Linux): 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Race condition
CWE: CWE-362
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 301785
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-23239

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.75/6.18.16/6.19.6/7.0-rc2
Patch: f7ad8b1d0e421c524604d5076b73232093490d5c/664e9df53226b4505a0894817ecad2c610ab11d8/e1512c1db9e8794d8d130addd2615ec27231d994

Timelineinfo

01/13/2026 CVE reserved
03/10/2026 +56 days Advisory disclosed
03/10/2026 +0 days VulDB entry created
05/20/2026 +71 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-23239 (🔒)
GCVE (CVE): GCVE-0-2026-23239
GCVE (VulDB): GCVE-100-350055
CERT Bund: WID-SEC-2026-0680 - Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 03/10/2026 19:38
Updated: 05/20/2026 21:47
Changes: 03/10/2026 19:38 (59), 03/11/2026 15:49 (2), 03/12/2026 06:17 (7), 03/13/2026 05:18 (1), 05/20/2026 21:47 (11)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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