Bug 2516500 (CVE-2026-72417)

Summary: CVE-2026-72417 kernel: netfilter: flowtable: Validate iph->ihl in nf_flow_ip4_tunnel_proto()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's netfilter flowtable component. Insufficient validation of the `iph->ihl` field in the `nf_flow_ip4_tunnel_proto()` function, when processing malformed IP (Internet Protocol) headers, could lead to an out-of-bounds access. This vulnerability could allow a remote attacker to trigger memory corruption.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-08-15 06:15:45 UTC 
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.
Comment 1 Keith Grant 2026-08-19 16:11:41 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081524-CVE-2026-72417-8c95@gregkh/T