CVE-2026-89563 Linux Kernel - Use After Free

Linux kernel ip6_tunnel contains a memory management flaw in ip6_tnl_xmit() caused by improper skb headroom expansion using skb_realloc_headroom(), letting kernel components potentially free stale skb pointers, exploit requires kernel-level interaction.

CVSS base score 7.8 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.14% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Use After Free
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
11 September 2026
Updated
15 October 2026

Vendor fix

Update to the latest Linux kernel version containing the fix using skb_cow_head() in ip6_tnl_xmit().

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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