CVE-2026-80875
Received Received - Intake

IPVS TCP State Handling Issue in Linux Kernel

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ipvs: use parsed transport offset in TCP state lookup TCP state handling reparses the skb to find the TCP header. For IPv6 it uses sizeof(struct ipv6hdr), while the surrounding IPVS code already parsed the packet with ip_vs_fill_iph_skb() and has the real transport-header offset in iph.len. This makes TCP state handling look at the wrong bytes when an IPv6 packet carries extension headers. Use the parsed transport offset passed down from ip_vs_set_state() when reading the TCP header. For IPv4 and for IPv6 packets without extension headers, the passed offset matches the previous value.

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Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-05
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
CVE-2026-80875
EUVD
EUVD-2026-71505

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves incorrect TCP state handling in IPVS (IP Virtual Server) for IPv6 packets. The code reparses the packet to find the TCP header but uses a fixed offset for IPv6 instead of the parsed transport offset. This causes issues when IPv6 packets include extension headers, leading to incorrect state lookups.

Detection Guidance

This vulnerability affects the Linux kernel's IPVS (IP Virtual Server) TCP state handling for IPv6 packets with extension headers. Detection requires checking kernel versions and IPVS configurations. Use commands like 'uname -a' to verify kernel version and 'lsmod | grep ip_vs' to check if IPVS is loaded. Monitor network traffic for malformed IPv6 packets with extension headers.

Impact Analysis

This vulnerability could allow attackers to manipulate TCP state handling in IPVS, potentially causing denial-of-service conditions or bypassing security mechanisms. Systems using IPVS for load balancing or network services may be affected, especially those handling IPv6 traffic with extension headers.

Mitigation Strategies

Apply the latest kernel update from your Linux distribution to patch this vulnerability. If immediate patching is not possible, disable IPVS for IPv6 traffic or restrict IPv6 extension header usage. Monitor vendor advisories for official patches and workarounds.

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