What is CVE-2026-31640?

CVE-2026-31640 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10, classified as a Memory Leak flaw (CWE-401), affecting Linux kernel versions from 6.16 onward and patched in 6.18.23, 6.19.13 and 7.0. CVE-2026-31640 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-31640?

CVE-2026-31640 has a CVSS score of 7.5 out of 10, rated High severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2026-31640?

Yes, CVE-2026-31640 has been patched. Fixed versions include 6.18.23, 6.19.13 and 7.0. If you are running Linux kernel 6.16 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-31640 actively exploited?

CVE-2026-31640 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is Memory Leak (CWE-401)?

The product does not release memory after use, causing gradual resource exhaustion. See MITRE CWE for full details: https://cwe.mitre.org/data/definitions/401.html

CVE-2026-31640

High

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix use of wrong skb when comparing queued RESP challenge serial In rxrpc_post_response(), the code should be comparing the challenge serial number from the cached response before deciding to switch to a newer response, but looks at the newer packet private data instead, rendering the comparison always false. Fix this by switching to look at the older packet. Fix further[1] to substitute the new packet in place of the old one if newer and also to release whichever we don't use.

Package Linux Kernel

Published 2026-04-24

Last modified 2026-04-27

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.5

out of 10

High

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Weakness type

CWE-401

CVE-2026-31640 is a Memory Leak vulnerability

What is Memory Leak?

The product does not release memory after use, causing gradual resource exhaustion. Learn more on MITRE CWE

Affected versions

Linux kernel versions 6.16 and later are affected. Fixed in 6.18.23, 6.19.13, 7.0 and their respective stable series.

Affected from

≥ 6.16

Fixed in

✓ 6.18.23 6.18.x ✓ 6.19.13 6.19.x ✓ 7.0

References

3 total

Kernel Git
https://git.kernel.org/stable/c/20386e7f8d97475b8d815873e246423317ec4260

Patch
Kernel Git
https://git.kernel.org/stable/c/9132b1a7bf83b4a8042fffbc99d075b727a16742

Patch
Kernel Git
https://git.kernel.org/stable/c/b33f5741bb187db8ff32e8f5b96def77cc94dfca

Patch

Details

CVE ID CVE-2026-31640

Severity High

CVSS score 7.5 / 10

CVSS version 3.1

Published 2026-04-24

Modified 2026-04-27

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-31640?

CVE-2026-31640 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 , classified as a Memory Leak flaw (CWE-401) . It affects Linux kernel versions from 6.16 onward and has been patched in 6.18.23, 6.19.13 and 7.0. CVE-2026-31640 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-31640?

CVE-2026-31640 has a CVSS score of 7.5 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2026-31640?

Yes. CVE-2026-31640 has been patched. Fixed versions include 6.18.23, 6.19.13 and 7.0. If you are running Linux kernel 6.16 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-31640 actively exploited?

No. CVE-2026-31640 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.