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CVE-2026-46120

ip6_gre: Use cached t->net in ip6erspan_changelink().

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.17, 5.10.258, 5.15.209, 6.1.175, 6.6.140, and 3 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

In the Linux kernel, the following vulnerability has been resolved: ip6_gre: Use cached t->net in ip6erspan_changelink(). After commit 5e72ce3e3980 ("net: ipv6: Use link netns in newlink() of rtnl_link_ops"), ip6erspan_newlink() correctly resolves the per-netns ip6gre hash via link_net. ip6erspan_changelink() was not converted in that series and still uses dev_net(dev), which diverges from the device's creation netns after IFLA_NET_NS_FD migration. This re-inserts the tunnel into the wrong per-netns hash. The original netns keeps a stale entry. When that netns is later destroyed, ip6gre_exit_rtnl_net() walks the stale entry, producing a slab-use-after-free reported by KASAN, followed by a kernel BUG at net/core/dev.c (LIST_POISON1) in unregister_netdevice_many_notify(). Reachable from an unprivileged user namespace (unshare --user --map-root-user --net). ip6gre_changelink() earlier in the same file already uses the cached t->net; only ip6erspan_changelink() has the wrong shape.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From 2d665034f239412927b1e71329f20f001c92da09 · fixed in 7bd0f2b162b426b343a114e1b329f0d8d14fdc6e; From 2d665034f239412927b1e71329f20f001c92da09 · fixed in 01b71ff2857d3598337de11e7840a8e3ff21553c; From 2d665034f239412927b1e71329f20f001c92da09 · fixed in 0fcf6731706f73494245a9c0d64f93bebf95bb51; From 2d665034f239412927b1e71329f20f001c92da09 · fixed in eca62bb0569de4d43a4dac06a2092a9d4ca1d702; From 2d665034f239412927b1e71329f20f001c92da09 · fixed in 311fdd26eb4443d43b909cc67a10f3a5fd1b21b2; From 2d665034f239412927b1e71329f20f001c92da09 · fixed in e70cfb40c3a99b232cd42c6a6a10f0d8e039dc82; From 2d665034f239412927b1e71329f20f001c92da09 · fixed in cf7fc624329e76c6394653d12353e1d033adea91; From 2d665034f239412927b1e71329f20f001c92da09 · fixed in 1d324c2f43f70c965f25c58cc3611c779adbe47e; From 4.16.12 · fixed in 4.17

  • Linux Linux

    4.17

  • KernelLinux

    From 4.17.0 · fixed in 5.10.258; From 5.11.0 · fixed in 5.15.209; From 5.16.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.140; From 6.7.0 · fixed in 6.12.88; From 6.13.0 · fixed in 6.18.30; From 6.19.0 · fixed in 7.0.7

References 8

git.kernel.org