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CVE-2023-53439

5.5 · MEDIUM

In the Linux kernel, the following vulnerability has been resolved: net: skb_partial_csum_set() fix against transport header magic value skb->transport_header uses the special 0xFFFF value to mar…

Published Sep 18, 2025CWE-401EPSS 0.15%

Overview

CVE-2023-53439 is a medium-severity vulnerability. It was published on September 18, 2025 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

net: skb_partial_csum_set() fix against transport header magic value

skb->transport_header uses the special 0xFFFF value

to mark if the transport header was set or not.

We must prevent callers to accidentaly set skb->transport_header

to 0xFFFF. Note that only fuzzers can possibly do this today.

syzbot reported:

WARNING: CPU: 0 PID: 2340 at include/linux/skbuff.h:2847 skb_transport_offset include/linux/skbuff.h:2956 [inline]

WARNING: CPU: 0 PID: 2340 at include/linux/skbuff.h:2847 virtio_net_hdr_to_skb+0xbcc/0x10c0 include/linux/virtio_net.h:103

Modules linked in:

CPU: 0 PID: 2340 Comm: syz-executor.0 Not tainted 6.3.0-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023

RIP: 0010:skb_transport_header include/linux/skbuff.h:2847 [inline]

RIP: 0010:skb_transport_offset include/linux/skbuff.h:2956 [inline]

RIP: 0010:virtio_net_hdr_to_skb+0xbcc/0x10c0 include/linux/vir

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Frequently asked questions

What is CVE-2023-53439?

CVE-2023-53439 is a medium-severity vulnerability. It was published on September 18, 2025 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2023-53439?

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2023-53439?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2023-53439?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2023-53439 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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