CVE Catalog

CVE-2026-80792

Unknown
Published: Translated: NVD NIST

Summary

In ip6_finish_output2(), a pointer to the IPv6 destination address is cached before invoking lwtunnel_xmit(), which can reallocate the skb head and free the memory. After LWTUNNEL_XMIT_CONTINUE, the stale pointer is used, leading to a use-after-free.

Risk Assessment

An attacker can exploit LWT-BPF or encapsulation to trigger a use-after-free, potentially causing data leaks, neighbour table poisoning, traffic misdirection, or system crashes.

Recommendation

Apply the patch that re-fetches the IPv6 header and destination address pointer after lwtunnel_xmit() returns LWTUNNEL_XMIT_CONTINUE.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ipv6: fix use-after-free in ip6_finish_output2() ip6_finish_output2() caches a pointer to the IPv6 destination address (daddr) before invoking lwtunnel_xmit(). The LWT-BPF transmit path or other encapsulation operations within lwtunnel_xmit() can reallocate the skb head, freeing the memory that daddr points to. When lwtunnel_xmit() returns LWTUNNEL_XMIT_CONTINUE, the function continues to use the stale daddr pointer to compute the nexthop and to look up or create the neighbour entry. This results in a use-after-free read, which can leak sensitive kernel data, pollute the neighbour table with arbitrary values, misdirect traffic, or crash the system. Fix this by re-fetching the IPv6 header and the destination address pointer after lwtunnel_xmit() returns LWTUNNEL_XMIT_CONTINUE, ensuring that the subsequent nexthop computation and neighbour lookup operate on valid memory.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS