What is CVE-2026-23240?

CVE-2026-23240 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10, classified as a Race Condition flaw (CWE-362), affecting Linux kernel versions from 5.3 onward and patched in 6.12.75, 6.18.16, 6.19.6 and others. CVE-2026-23240 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-23240?

CVE-2026-23240 has a CVSS score of 9.8 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-23240?

Yes, CVE-2026-23240 has been patched. Fixed versions include 6.12.75, 6.18.16, 6.19.6 and others. If you are running Linux kernel 5.3 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-23240 actively exploited?

CVE-2026-23240 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Race Condition (CWE-362)?

The product contains a code sequence that can run concurrently with other code, creating unexpected states. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/362.html

CVE-2026-23240

Critical

In the Linux kernel, the following vulnerability has been resolved: tls: Fix race condition in tls_sw_cancel_work_tx() This issue was discovered during a code audit. After cancel_delayed_work_sync() is called from tls_sk_proto_close(), tx_work_handler() can still be scheduled from paths such as the Delayed ACK handler or ksoftirqd. As a result, the tx_work_handler() worker may dereference a freed TLS object. The following is a simple race scenario: cpu0 cpu1 tls_sk_proto_close() tls_sw_cancel_work_tx() tls_write_space() tls_sw_write_space() if (!test_and_set_bit(BIT_TX_SCHEDULED, &tx_ctx->tx_bitmask)) set_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask); cancel_delayed_work_sync(&ctx->tx_work.work); schedule_delayed_work(&tx_ctx->tx_work.work, 0); To prevent this race condition, cancel_delayed_work_sync() is replaced with disable_delayed_work_sync().

Package Linux Kernel

Published 2026-03-10

Last modified 2026-05-20

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.8

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness type

CWE-362

CVE-2026-23240 is a Race Condition vulnerability

What is Race Condition?

The product contains a code sequence that can run concurrently with other code, creating unexpected states. Learn more on MITRE CWE

Affected versions

Linux kernel versions 5.3 and later are affected. Fixed in 6.12.75, 6.18.16, 6.19.6, 7.0 and their respective stable series.

Affected from

≥ 5.3

Fixed in

✓ 6.12.75 6.12.x ✓ 6.18.16 6.18.x ✓ 6.19.6 6.19.x ✓ 7.0

References

4 total

Kernel Git
https://git.kernel.org/stable/c/17153f154f80be2b47ebf52840f2d8f724eb2f3b

Patch
Kernel Git
https://git.kernel.org/stable/c/7bb09315f93dce6acc54bf59e5a95ba7365c2be4

Patch
Kernel Git
https://git.kernel.org/stable/c/854cd32bc74fe573353095e90958490e4e4d641b

Patch
Kernel Git
https://git.kernel.org/stable/c/a5de36d6cee74a92c1a21b260bc507e64bc451de

Patch

Details

CVE ID CVE-2026-23240

Severity Critical

CVSS score 9.8 / 10

CVSS version 3.1

Published 2026-03-10

Modified 2026-05-20

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-23240?

CVE-2026-23240 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.8 out of 10 , classified as a Race Condition flaw (CWE-362) . It affects Linux kernel versions from 5.3 onward and has been patched in 6.12.75, 6.18.16, 6.19.6 and others. CVE-2026-23240 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-23240?

CVE-2026-23240 has a CVSS score of 9.8 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-23240?

Yes. CVE-2026-23240 has been patched. Fixed versions include 6.12.75, 6.18.16, 6.19.6 and others. If you are running Linux kernel 5.3 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-23240 actively exploited?

No. CVE-2026-23240 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.