CVE-2026-68127

Received Received - Intake

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

Publication date: 2026-08-10

Last updated on: 2026-10-19

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

2026-10-19

Generated

2026-11-08

AI Q&A

2026-08-10

EPSS Evaluated

2026-11-07

NVD

CVE-2026-68127

EUVD

EUVD-2026-55508

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

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.

Detection Guidance

This vulnerability may trigger a slab-use-after-free in the Linux kernel's ILA module when processing specific IPv6 packets. Detection requires kernel logging for KASAN errors or slab corruption events. Monitor kernel logs with: dmesg | grep -i kasan or journalctl -k | grep -i slab. If you suspect exploitation, check for CAP_NET_ADMIN-related anomalies in network traffic handling.

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.

Compliance Impact

This vulnerability does not directly impact compliance with GDPR, HIPAA, or similar standards. It is a low-level kernel memory corruption issue in the Linux IPv6 stack that could allow remote code execution or denial of service if exploited. Compliance implications would depend on system configuration and use case rather than the vulnerability itself.

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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