What is CVE-2026-23331?

CVE-2026-23331 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 6.13 onward and patched in 6.18.17, 6.19.7 and 7.0. CVE-2026-23331 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-23331?

CVE-2026-23331 has a CVSS score of 5.5 out of 10, rated Medium severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Is there a patch available for CVE-2026-23331?

Yes, CVE-2026-23331 has been patched. Fixed versions include 6.18.17, 6.19.7 and 7.0. If you are running Linux kernel 6.13 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-23331 actively exploited?

CVE-2026-23331 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-23331

Medium

In the Linux kernel, the following vulnerability has been resolved: udp: Unhash auto-bound connected sk from 4-tuple hash table when disconnected. Let's say we bind() an UDP socket to the wildcard address with a non-zero port, connect() it to an address, and disconnect it from the address. bind() sets SOCK_BINDPORT_LOCK on sk->sk_userlocks (but not SOCK_BINDADDR_LOCK), and connect() calls udp_lib_hash4() to put the socket into the 4-tuple hash table. Then, __udp_disconnect() calls sk->sk_prot->rehash(sk). It computes a new hash based on the wildcard address and moves the socket to a new slot in the 4-tuple hash table, leaving a garbage in the chain that no packet hits. Let's remove such a socket from 4-tuple hash table when disconnected. Note that udp_sk(sk)->udp_portaddr_hash needs to be udpated after udp_hash4_dec(hslot2) in udp_unhash4().

Package Linux Kernel

Published 2026-03-25

Last modified 2026-04-23

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

5.5

out of 10

Medium

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

High

Vector string

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

Affected versions

Linux kernel versions 6.13 and later are affected. Fixed in 6.18.17, 6.19.7, 7.0 and their respective stable series.

Affected from

≥ 6.13

Fixed in

✓ 6.18.17 6.18.x ✓ 6.19.7 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-23331 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/3b8f104880c104151f8c30f2f89df81fb59a286c
Patch
Kernel patch commit
https://git.kernel.org/stable/c/6996a2d2d0a64808c19c98002aeb5d9d1b2df6a4
Patch
Kernel patch commit
https://git.kernel.org/stable/c/b955350778b8715e1b7885179979b3a68221c0fb
Patch

Details

CVE ID CVE-2026-23331

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2026-03-25

Modified 2026-04-23

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-23331?

CVE-2026-23331 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 6.13 onward and has been patched in 6.18.17, 6.19.7 and 7.0. CVE-2026-23331 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-23331?

CVE-2026-23331 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
Is there a patch available for CVE-2026-23331?

Yes — CVE-2026-23331 has been patched. Fixed versions include 6.18.17, 6.19.7 and 7.0. If you are running Linux kernel 6.13 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-23331 actively exploited?

No — CVE-2026-23331 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.