CVE-2026-63922
Received Received - Intake

IPv6 Header Option Handling Vulnerability in Linux Kernel

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: exthdrs: refresh nh after handling HAO option ip6_parse_tlv() caches skb_network_header(skb) in nh while walking IPv6 TLVs. ipv6_dest_hao() may call pskb_expand_head() for a cloned skb, which can move the skb head and invalidate the cached network header pointer. Refresh nh after ipv6_dest_hao() returns so any trailing padding or TLVs are parsed from the current skb head. This matches the existing pattern used in ip6_parse_tlv() after helpers that can modify skb header storage.

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-63922
EUVD
EUVD-2026-45695

Affected Vendors & Products

Currently, no data is known.

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Exploitability

CWE
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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 a network header pointer becoming invalid after processing an IPv6 header option. The function ip6_parse_tlv caches the network header pointer while parsing IPv6 TLVs. If ipv6_dest_hao modifies the skb via pskb_expand_head, the header pointer becomes stale. The fix refreshes the cached pointer after this operation to ensure correct parsing of remaining data.

Detection Guidance

This vulnerability is specific to the Linux kernel's IPv6 handling and requires kernel-level inspection. Detection involves checking kernel logs for related errors or verifying if your kernel version includes the fix. Commands like 'uname -a' to check kernel version or 'dmesg | grep -i ipv6' to inspect logs may help.

Impact Analysis

This could lead to packet parsing errors or crashes in systems using IPv6 with specific header options. Attackers might exploit this to cause denial-of-service conditions or unexpected behavior in network services relying on IPv6.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or other common standards and regulations. It is a low-level Linux kernel issue related to IPv6 header parsing that could lead to memory corruption or crashes but does not involve data exposure or privacy violations.

Mitigation Strategies

Update your Linux kernel to a patched version that includes the fix for this vulnerability. Monitor vendor advisories for kernel updates and apply them promptly. If immediate patching is not possible, consider restricting IPv6 traffic or disabling it if not required.

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