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CVE-2026-23016

5.5 · MEDIUM
Published Jan 31, 2026 linux EPSS 0.13% (3th pctl)

Overview

CVE-2026-23016 is a medium-severity vulnerability affecting linux linux_kernel. It was published on January 31, 2026 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:

inet: frags: drop fraglist conntrack references

Jakub added a warning in nf_conntrack_cleanup_net_list() to make debugging

leaked skbs/conntrack references more obvious.

syzbot reports this as triggering, and I can also reproduce this via

ip_defrag.sh selftest:

conntrack cleanup blocked for 60s

WARNING: net/netfilter/nf_conntrack_core.c:2512

[..]

conntrack clenups gets stuck because there are skbs with still hold nf_conn

references via their frag_list.

net.core.skb_defer_max=0 makes the hang disappear.

Eric Dumazet points out that skb_release_head_state() doesn't follow the

fraglist.

ip_defrag.sh can only reproduce this problem since

commit 6471658dc66c ("udp: use skb_attempt_defer_free()"), but AFAICS this

problem could happen with TCP as well if pmtu discovery is off.

The relevant problem path for udp is:

1. netns emits fragmented packets

2. nf_defrag_v6_hook reassembles them (in output hook)

3. reasse

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. 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.

Affected Products

Vendor Product Versions Status
linux linux_kernel >= 6.18.1, < 6.18.6 Affected

Frequently Asked Questions

What is CVE-2026-23016?

CVE-2026-23016 is a medium-severity vulnerability affecting linux linux_kernel. It was published on January 31, 2026 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2026-23016?

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-2026-23016?

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. 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-2026-23016?

CyberStrike's AI-powered security agents can automatically detect CVE-2026-23016 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.