CVE-2026-53267 Linux CVE debrief

Who should care

System administrators and security teams responsible for Linux kernel-based systems should be aware of this vulnerability. The vulnerability requires local access to the system, but can potentially lead to privilege escalation. Therefore, it is essential to apply the necessary patches or mitigations to prevent exploitation.

Technical summary

The vulnerability is located in the nft_ct module of the Linux kernel's netfilter component. The bug is caused by inadequate checks on the conntrack object's type, allowing a template object to be treated as a real conntrack object. When a template conntrack object is passed to the nft_ct_get_eval function, it triggers a 16-byte memcpy operation on the kernel stack, potentially overflowing it. The vulnerability has been resolved by adding checks to reject template conntrack objects at evaluation time and bounding the address copy in NFT_CT_SRC / NFT_CT_DST by priv->len instead of by nf_ct_l3num(ct).

Defensive priority

High priority should be given to patching or mitigating this vulnerability, as it can potentially lead to privilege escalation. System administrators and security teams should review their Linux kernel-based systems and apply the necessary patches or mitigations.

Recommended defensive actions

• Apply the official patches provided by the Linux kernel maintainers.
• Review and update Linux kernel-based systems to ensure they are running with the patched version.
• Implement compensating controls, such as monitoring and intrusion detection systems, to detect potential exploitation attempts.
• Perform thorough vulnerability assessments and penetration testing to identify potential vulnerabilities in the system.
• Develop and implement a comprehensive incident response plan to respond to potential security incidents.

Evidence notes

The vulnerability was discovered by an unknown researcher and reported to the Linux kernel maintainers. The vulnerability has been assigned a CVSS score of 7.8 and a severity of HIGH. The vulnerability affects the Linux kernel's netfilter component and can be exploited by an attacker with local access to the system.

Official resources