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CVE PROGRAM SOURCE RECORDUnscored

CVE-2025-71097

ipv4: Fix reference count leak when using error routes with nexthop objects

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: ipv4: Fix reference count leak when using error routes with nexthop objects When a nexthop object is deleted, it is marked as dead and then fib_table_flush() is called to flush all the routes that are using the dead nexthop. The current logic in fib_table_flush() is to only flush error routes (e.g., blackhole) when it is called as part of network namespace dismantle (i.e., with flush_all=true). Therefore, error routes are not flushed when their nexthop object is deleted: # ip link add name dummy1 up type dummy # ip nexthop add id 1 dev dummy1 # ip route add 198.51.100.1/32 nhid 1 # ip route add blackhole 198.51.100.2/32 nhid 1 # ip nexthop del id 1 # ip route show blackhole 198.51.100.2 nhid 1 dev dummy1 As such, they keep holding a reference on the nexthop object which in turn holds a reference on the nexthop device, resulting in a reference count leak: # ip link del dev dummy1 [ 70.516258] unregister_netdevice: waiting for dummy1 to become free. Usage count = 2 Fix by flushing error routes when their nexthop is marked as dead. IPv6 does not suffer from this problem.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e to < 5de7ad7e18356e39e8fbf7edd185a5faaf4f385aaffected
  • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e to < 33ff5c207c873215e54e6176624ed57423cb7deaaffected
  • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e to < 30386e090c49e803c0616a7147e43409c32a2b0eaffected
  • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e to < 5979338c83012110ccd45cae6517591770bfe536affected
  • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e to < ee4183501ea556dca31f5ffd8690aa9fd25b609faffected
  • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e to < e3fc381320d04e4a74311e576a86cac49a16fc43affected
  • 493ced1ac47c48bb86d9d4e8e87df8592be85a0e to < ac782f4e3bfcde145b8a7f8af31d9422d94d172aaffected

Linux Linux

Default version status: affected

  • 5.3affected
  • 0 to < 5.3unaffected
  • 5.10.248 to ≤ 5.10.*unaffected
  • 5.15.198 to ≤ 5.15.*unaffected
  • 6.1.160 to ≤ 6.1.*unaffected
  • 6.6.120 to ≤ 6.6.*unaffected
  • 6.12.64 to ≤ 6.12.*unaffected
  • 6.18.4 to ≤ 6.18.*unaffected
  • 6.19 to ≤ *unaffected

References