Linux Kernel up to 7.1.4/7.2-rc2 flowtable input validation

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.1.4/7.2-rc2. It has been classified as critical. Affected by this vulnerability is an unknown functionality of the component flowtable. This manipulation causes input validation. This vulnerability is tracked as CVE-2026-72249. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 7.1.4/7.2-rc2 and classified as critical. Affected by this vulnerability is an unknown code block of the component flowtable. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: use dst in this direction when pushing IPIP header When pushing the IPIP header, the route of the other direction is used to calculate the headroom, use the route in this direction. Accessing the other tuple to set the IP source and destination is fine because this tuple does not provide such information to avoid storing redundant information. However, this tuple already provides the dst for this direction, this went unnoticed because this bug affects headroom and iph->frag_off only at this stage.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-72249 since 08/09/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 7.1.5 or 7.2-rc3 eliminates this vulnerability. Applying the patch ecb78fbb03d3f86e2e93767875e273308086a424/c328b90c17fc5fa7786503695152880b2afb9326 is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.2-rc1
• 7.2-rc2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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