net: appletalk: fix NULL pointer dereference in aarp_send_ddp()

Summary

In the Linux kernel, the following vulnerability has been resolved: net: appletalk: fix NULL pointer dereference in aarp_send_ddp() aarp_send_ddp() calls atalk_find_dev_addr(dev) in the LocalTalk fast path without checking for NULL. When the device has no AppleTalk interface configured (dev->atalk_ptr == NULL), this leads to a NULL pointer dereference at the at->s_net access. KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:aarp_send_ddp (net/appletalk/aarp.c:552 (discriminator 2)) Call Trace: <TASK> atalk_sendmsg (net/appletalk/ddp.c:1715) __sys_sendto (net/socket.c:2265 (discriminator 1)) __x64_sys_sendto (net/socket.c:2272) do_syscall_64 (arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Add a NULL check consistent with the other callers of atalk_find_dev_addr().

Timeline

1. Sep 24, 2026, 4:02 PM UTCCVE published
2. Oct 3, 2026, 10:57 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 51cc5e756cec6071ffc620076aebcf5bae936668; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 8c4b9ceb1be780588c1c50d573d5ee308e0874d2; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in d643fd42ad96f19b5ce5cb11824fefa617191dbe; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 542c1dd41e1b0cd1c2c3ba8091c7d882eea0d680; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 8fc30f0cdf4207a5aa2341c0a98d0f1713b3ce2c; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 83899a056aeb120898a6e3a989971fc63e274e2e; From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 · fixed in 9e7f36ab5b7bf68463faa5f7b926fea8f35597bb

• Linux Linux

  2.6.12

• KernelLinux

  From 2.6.12 · fixed in 5.10.271; From 5.11.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.53

References 7