CVE-2026-68127
Received Received - Intake

Use-After-Free in Linux Kernel ILA IPv6 Header Handling

Publication date: 2026-08-10

Last updated on: 2026-08-10

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ila: reload IPv6 header after pskb_may_pull in checksum adjust ila_csum_adjust_transport() caches ip6h = ipv6_hdr(skb) before calling pskb_may_pull(). On a non-linear skb whose transport header sits in a page fragment, pskb_may_pull() can call __pskb_pull_tail() / pskb_expand_head() and free the old skb head, leaving ip6h dangling; the following get_csum_diff(ip6h, p) then reads freed memory. ila_update_ipv6_locator() uses ip6h (and the iaddr derived from it) again after the csum-adjust call and additionally writes the new locator through that pointer. Impact: a remote IPv6 packet routed through a configured ILA csum-adjust-transport route or receive-side mapping triggers a slab-use-after-free in ila_update_ipv6_locator() (KASAN). The route or mapping requires CAP_NET_ADMIN to configure, but trigger packets are unauthenticated once it exists. Reload ip6h after each pskb_may_pull() in ila_csum_adjust_transport() before the csum-diff read. In ila_update_ipv6_locator() only the ILA_CSUM_ADJUST_TRANSPORT case pulls the skb, so reload ip6h and iaddr in that case alone before the destination-address write; the neutral-map modes never pull and keep their cached pointers.

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Meta Information

Published
2026-08-10
Last Modified
2026-08-10
Generated
2026-08-10
AI Q&A
2026-08-10
EPSS Evaluated
N/A
NVD
CVE-2026-68127
EUVD
EUVD-2026-55508

Affected Vendors & Products

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

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a use-after-free flaw in the Linux kernel's ILA (Identifier Locator Address) implementation. It occurs when processing IPv6 packets that require checksum adjustments. The issue arises because the code caches a pointer to the IPv6 header before validating the packet's structure, leading to a dangling pointer after memory reallocation. This can cause a slab-use-after-free when the cached pointer is later accessed.

Impact Analysis

If exploited, this vulnerability could allow an attacker to crash the system or potentially execute arbitrary code with kernel privileges. The attack requires CAP_NET_ADMIN privileges to set up a malicious route or mapping, but unauthenticated packets can trigger the flaw once the route exists. Systems using ILA features with IPv6 are at risk.

Mitigation Strategies

Update the Linux kernel to a patched version that resolves the ila_csum_adjust_transport() vulnerability. Apply kernel patches addressing slab-use-after-free in ila_update_ipv6_locator().

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