atm: clip: Fix potential null-ptr-deref in to_atmarpd().

Summary

In the Linux kernel, the following vulnerability has been resolved: atm: clip: Fix potential null-ptr-deref in to_atmarpd(). atmarpd is protected by RTNL since commit f3a0592b37b8 ("[ATM]: clip causes unregister hang"). However, it is not enough because to_atmarpd() is called without RTNL, especially clip_neigh_solicit() / neigh_ops->solicit() is unsleepable. Also, there is no RTNL dependency around atmarpd. Let's use a private mutex and RCU to protect access to atmarpd in to_atmarpd().

Timeline

1. Jul 25, 2025, 3:27 PM UTCCVE published
2. Oct 15, 2026, 9:50 PM UTCCISA SSVC assessment

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

3. Oct 15, 2026, 9:52 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in a4c5785feb979cd996a99cfaad8bf353b2e79301; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 70eac9ba7ce25d99c1d99bbf4ddb058940f631f9; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 3251ce3979f41bd228f77a7615f9dd616d06a110; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in ee4d9e4ddf3f9c4ee2ec0a3aad6196ee36d30e57; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 06935c50cfa3ac57cce80bba67b6d38ec1406e92; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 36caab990b69ef4eec1d81c52a19f080b7daa059; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in f58e4270c73e7f086322978d585ea67c8076ce49; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 706cc36477139c1616a9b2b96610a8bb520b7119

• Linux Linux

  2.6.12

• KernelLinux

  From 2.6.12 · fixed in 5.4.296; From 5.5.0 · fixed in 5.10.240; From 5.11.0 · fixed in 5.15.189; From 5.16.0 · fixed in 6.1.146; From 6.2.0 · fixed in 6.6.99; From 6.7.0 · fixed in 6.12.39; From 6.13.0 · fixed in 6.15.7

References 8