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CVE-2026-23304

ipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.77, and 2 more
None on Exploit-DB, Metasploit or GitHub

Summary

In the Linux kernel, the following vulnerability has been resolved: ipv6: fix NULL pointer deref in ip6_rt_get_dev_rcu() l3mdev_master_dev_rcu() can return NULL when the slave device is being un-slaved from a VRF. All other callers deal with this, but we lost the fallback to loopback in ip6_rt_pcpu_alloc() -> ip6_rt_get_dev_rcu() with commit 4832c30d5458 ("net: ipv6: put host and anycast routes on device with address"). KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f] RIP: 0010:ip6_rt_pcpu_alloc (net/ipv6/route.c:1418) Call Trace: ip6_pol_route (net/ipv6/route.c:2318) fib6_rule_lookup (net/ipv6/fib6_rules.c:115) ip6_route_output_flags (net/ipv6/route.c:2607) vrf_process_v6_outbound (drivers/net/vrf.c:437) I was tempted to rework the un-slaving code to clear the flag first and insert synchronize_rcu() before we remove the upper. But looks like the explicit fallback to loopback_dev is an established pattern. And I guess avoiding the synchronize_rcu() is nice, too.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 4832c30d5458387ff2533ff66fbde26ad8bb5a2d · fixed in d542e2ac7f9e288d49735be0775611547ca4e0ee; From 4832c30d5458387ff2533ff66fbde26ad8bb5a2d · fixed in a73fe9f4ae84a239d5b2686f47a58c158aee2eb4; From 4832c30d5458387ff2533ff66fbde26ad8bb5a2d · fixed in 4a48fe59f29f673a3d042d679f26629a9c3e29d4; From 4832c30d5458387ff2533ff66fbde26ad8bb5a2d · fixed in 581800298313c9fd75e94985e6d37d21b7e35d34; From 4832c30d5458387ff2533ff66fbde26ad8bb5a2d · fixed in 3310fc11fc47387d1dd4759b0bc961643ea11c7f; From 4832c30d5458387ff2533ff66fbde26ad8bb5a2d · fixed in 0b5a7826020706057cc5a9d9009e667027f221ee; From 4832c30d5458387ff2533ff66fbde26ad8bb5a2d · fixed in ae88c8256547b63980770a9ea7be73a15900d27e; From 4832c30d5458387ff2533ff66fbde26ad8bb5a2d · fixed in 2ffb4f5c2ccb2fa1c049dd11899aee7967deef5a

  • Linux Linux

    4.14

  • KernelLinux

    From 4.14.0 · fixed in 5.10.253; From 5.11.0 · fixed in 5.15.203; From 5.16.0 · fixed in 6.1.167; From 6.2.0 · fixed in 6.6.130; From 6.7.0 · fixed in 6.12.77; From 6.13.0 · fixed in 6.18.17; From 6.19.0 · fixed in 6.19.7

References 8

git.kernel.org