CVE-2026-89983 PUBLISHED

i2c: core: fix debugfs UAF on adapter removal

Assigner: Linux
Reserved: 11.09.2026 Published: 16.09.2026 Updated: 16.09.2026

In the Linux kernel, the following vulnerability has been resolved:

i2c: core: fix debugfs UAF on adapter removal

i2c_del_adapter() frees the adapter's debugfs directory before it unregisters the adapter device, but the new_device sysfs attribute stays writable until device_del(). A write racing with removal still reaches i2c_device_probe(), which passes the freed adap->debugfs to debugfs_create_dir() as the new client's parent:

BUG: KASAN: slab-use-after-free in lookup_noperm_common+0x407/0x430 Read of size 4 at addr ffff88803ef87810 by task syz.0.61/6090 lookup_noperm_common+0x407/0x430 simple_start_creating+0x9c/0x110 debugfs_start_creating+0xdb/0x1a0 debugfs_create_dir+0x24/0x350 i2c_device_probe+0x814/0xbf0

It's technically possible to create a client after i2c_deregister_clients has run. That client will never be unregistered and make wait_for_completion hang.

Close the window by removing the new_device attribute at the start of i2c_del_adapter(). device_remove_file() will drain any clients left.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 0e8926abfd7aee220e44be5566affd7a8580b50e to dc33a9762538b3250ed6b5644a4d44c748be33a6 (excl.)
  • affected from e2a268b0f512fb18ae5961b1fdfaf610ed6bd661 to 1f1bcd4eca6caa3e4258d9a31925112539406eb6 (excl.)
  • affected from 4a2be5a72865bdd219b2d8c327b9fa03e87a4a9e to f9094ace03e0a532cc6505d2e97b61ae738da4ed (excl.)
  • affected from 73febd775bdbdb98c81255ff85773ac410ded5c4 to 643fb872aa04342d27dbef52b2b3cf3fe71b2c7b (excl.)
  • affected from 73febd775bdbdb98c81255ff85773ac410ded5c4 to 112b3d48084c820bbccf41d9783fd122e3ac4cb0 (excl.)
  • affected from 73febd775bdbdb98c81255ff85773ac410ded5c4 to 552836be2d95c688eede6371f85532abe1a71232 (excl.)
  • affected from 73febd775bdbdb98c81255ff85773ac410ded5c4 to b15b548d52b43ba8ac4652bc2c7244a8dd1e9622 (excl.)
  • affected from 5.15.168 to 5.15.221 (excl.)
  • affected from 6.1.113 to 6.1.188 (excl.)
  • affected from 6.6.55 to 6.6.157 (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 6.8 is affected
  • unaffected from 0 to 6.8 (excl.)
  • unaffected from 5.15.221 to 5.15.* (incl.)
  • unaffected from 6.1.188 to 6.1.* (incl.)
  • unaffected from 6.6.157 to 6.6.* (incl.)
  • unaffected from 6.12.110 to 6.12.* (incl.)
  • unaffected from 6.18.51 to 6.18.* (incl.)
  • unaffected from 7.2.5 to 7.2.* (incl.)
  • unaffected from 7.3-rc1 to * (incl.)

References