CVE-2026-72417

Received Received - Intake

Linux Kernel IP Header Validation Bypass in Netfilter Flowtable

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: Validate iph->ihl in nf_flow_ip4_tunnel_proto() Add sanity check for iph->ihl field in nf_flow_ip4_tunnel_proto() before using it to compute the header size, avoiding out-of-bounds access with malformed IP headers. While at it, use iph->protocol instead of the hardcoded IPPROTO_IPIP constant when setting ctx->tun.proto and reference ctx->tun.hdr_size when updating ctx->offset.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-72417

EUVD

EUVD-2026-59316

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a missing validation check on the IP header length field (iph->ihl) in the nf_flow_ip4_tunnel_proto() function. This could allow an attacker to craft malformed IP headers that cause out-of-bounds memory access when the kernel processes network traffic.

Detection Guidance

This vulnerability involves a lack of validation of the iph->ihl field in the Linux kernel's netfilter flowtable code. Detection would typically require inspecting kernel logs for out-of-bounds access errors or crashes related to netfilter operations. Check for kernel oops messages or segmentation faults in system logs after processing malformed IP packets.

Impact Analysis

This vulnerability could allow an attacker to crash the system or potentially execute arbitrary code with kernel privileges by sending specially crafted network packets. This may lead to denial of service or unauthorized access to sensitive data on affected systems.

Compliance Impact

This vulnerability involves a potential out-of-bounds access in the Linux kernel's netfilter flowtable due to improper validation of IP header fields. While it does not directly impact data protection standards like GDPR or HIPAA, it could lead to system instability or crashes if exploited, potentially causing denial-of-service conditions that might affect the availability of systems handling sensitive data.

Mitigation Strategies

Apply the latest Linux kernel security patches that address this issue. Update your system to a kernel version that includes the fix for CVE-2026-72417. If immediate patching is not possible, consider disabling the flowtable feature in netfilter as a temporary workaround.

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