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CVE-2026-80792

ipv6: fix use-after-free in ip6_finish_output2()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.267, 5.5, 5.15.218, 6.1.185, 6.6.154, and 4 more
None on Exploit-DB, Metasploit or GitHub

Summary

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 4132c4ad00ddbf3a175ea0d2c775b662a32f4c85 · fixed in 75e0a544ebe9af663ef53ca21e9e9185c51fb54a; From e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 · fixed in c95f01b78266828a57060d754fcbfc92123a98ed; From e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 · fixed in d960881b9312e781a3429aabceb223ce6b7c882f; From e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 · fixed in 087ee0d914aaae929f1660c9ca878e367655ba1a; From e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 · fixed in 3c770ac4e6f07af7c7b40c474a3efc61ffed7862; From e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 · fixed in 3dc98e5fe82d069dd29b124ffbdb679331dfea43; From e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 · fixed in 99219c82804f266189388e8bf1cf5135d10d5515; From e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 · fixed in 73a187384a8c8b983c7fea046d716b6752a1e7a3; From e415ed3a4b8b246ee5e9d109ff5153efcf96b9f2 · fixed in d0d48d999b0eee6bb176ef4e39d9be868fa80f7e; From 5.10.233 · fixed in 5.10.267; From 5.4.289 · fixed in 5.5

  • Linux Linux

    5.15

  • KernelLinux

    fixed in 5.10.267; From 5.11.0 · fixed in 5.15.218; From 5.15.0 · fixed in 6.1.185; From 5.16.0 · fixed in 6.6.154; From 6.2.0 · fixed in 6.12.106; From 6.7.0 · fixed in 6.18.47; From 6.13.0 · fixed in 7.1.11; From 6.19.0 · fixed in 7.2.1

References 9

git.kernel.org