CVE-2026-80792
Description
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.
How to fix
- Linux Linux75e0a544ebe9af663ef53ca21e9e9185c51fb54a, c95f01b78266828a57060d754fcbfc92123a98ed, d960881b9312e781a3429aabceb223ce6b7c882f, 087ee0d914aaae929f1660c9ca878e367655ba1a, 3c770ac4e6f07af7c7b40c474a3efc61ffed7862, 3dc98e5fe82d069dd29b124ffbdb679331dfea43, 99219c82804f266189388e8bf1cf5135d10d5515, 73a187384a8c8b983c7fea046d716b6752a1e7a3, d0d48d999b0eee6bb176ef4e39d9be868fa80f7e, 5.10.267, 5.5 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 4132c4ad00ddbf3a175ea0d2c775b662a32f4c85 ≤ v < 75e0a544ebe9af663ef53ca21e9e9185c51fb54a, e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 ≤ v < c95f01b78266828a57060d754fcbfc92123a98ed, e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 ≤ v < d960881b9312e781a3429aabceb223ce6b7c882f, e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 ≤ v < 087ee0d914aaae929f1660c9ca878e367655ba1a, e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 ≤ v < 3c770ac4e6f07af7c7b40c474a3efc61ffed7862, e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 ≤ v < 3dc98e5fe82d069dd29b124ffbdb679331dfea43, e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 ≤ v < 99219c82804f266189388e8bf1cf5135d10d5515, e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 ≤ v < 73a187384a8c8b983c7fea046d716b6752a1e7a3, e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 ≤ v < d0d48d999b0eee6bb176ef4e39d9be868fa80f7e, 1598154fd28ffa4a55beae1970475fd6776554b6, 5.10.233 ≤ v < 5.10.267, 5.4.289 ≤ v < 5.5, 5.15 | 75e0a544ebe9af663ef53ca21e9e9185c51fb54a, c95f01b78266828a57060d754fcbfc92123a98ed, d960881b9312e781a3429aabceb223ce6b7c882f, 087ee0d914aaae929f1660c9ca878e367655ba1a, 3c770ac4e6f07af7c7b40c474a3efc61ffed7862, 3dc98e5fe82d069dd29b124ffbdb679331dfea43, 99219c82804f266189388e8bf1cf5135d10d5515, 73a187384a8c8b983c7fea046d716b6752a1e7a3, d0d48d999b0eee6bb176ef4e39d9be868fa80f7e, 5.10.267, 5.5 |
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