CVE-2026-63922 ipv6: exthdrs: refresh nh after handling HAO option

What is CVE-2026-63922?

CVE-2026-63922 is a critical use after free vulnerability in Linux kernel, published on 19 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-416

Which versions are affected by CVE-2026-63922?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-63922?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-63922 being exploited?

There is no known exploitation of CVE-2026-63922 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-63922, DEBIAN-CVE-2026-63922, GHSA-5w2v-4j6c-44h8, ROOT-OS-DEBIAN-11-CVE-2026-63922, ROOT-OS-UBUNTU-2204-CVE-2026-63922, UBUNTU-CVE-2026-63922.