CVE-2026-89983

i2c: core: fix debugfs UAF on adapter removal

State: Published
Severity: Not scored
Published: Sep 16, 2026
Updated: Oct 19, 2026
Reserved: Sep 11, 2026

Description

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.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	0e8926abfd7aee220e44be5566affd7a8580b50e to before dc33a9762538b3250ed6b5644a4d44c748be33a6Affected e2a268b0f512fb18ae5961b1fdfaf610ed6bd661 to before 1f1bcd4eca6caa3e4258d9a31925112539406eb6Affected 4a2be5a72865bdd219b2d8c327b9fa03e87a4a9e to before f9094ace03e0a532cc6505d2e97b61ae738da4edAffected 73febd775bdbdb98c81255ff85773ac410ded5c4 to before 643fb872aa04342d27dbef52b2b3cf3fe71b2c7bAffected 73febd775bdbdb98c81255ff85773ac410ded5c4 to before 112b3d48084c820bbccf41d9783fd122e3ac4cb0Affected 73febd775bdbdb98c81255ff85773ac410ded5c4 to before 552836be2d95c688eede6371f85532abe1a71232Affected 73febd775bdbdb98c81255ff85773ac410ded5c4 to before b15b548d52b43ba8ac4652bc2c7244a8dd1e9622Affected 5.15.168 to before 5.15.221Affected 6.1.113 to before 6.1.188Affected 6.6.55 to before 6.6.157Affected
LinuxLinux	6.8Affected before 6.8Not affected 5.15.221 through 5.15.Not affected 6.1.188 through 6.1.Not affected 6.6.157 through 6.6.Not affected 6.12.110 through 6.12.Not affected 6.18.51 through 6.18.Not affected 7.2.5 through 7.2.Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

0e8926abfd7aee220e44be5566affd7a8580b50e to before dc33a9762538b3250ed6b5644a4d44c748be33a6Affected
e2a268b0f512fb18ae5961b1fdfaf610ed6bd661 to before 1f1bcd4eca6caa3e4258d9a31925112539406eb6Affected
4a2be5a72865bdd219b2d8c327b9fa03e87a4a9e to before f9094ace03e0a532cc6505d2e97b61ae738da4edAffected
73febd775bdbdb98c81255ff85773ac410ded5c4 to before 643fb872aa04342d27dbef52b2b3cf3fe71b2c7bAffected
73febd775bdbdb98c81255ff85773ac410ded5c4 to before 112b3d48084c820bbccf41d9783fd122e3ac4cb0Affected
73febd775bdbdb98c81255ff85773ac410ded5c4 to before 552836be2d95c688eede6371f85532abe1a71232Affected
73febd775bdbdb98c81255ff85773ac410ded5c4 to before b15b548d52b43ba8ac4652bc2c7244a8dd1e9622Affected
5.15.168 to before 5.15.221Affected
6.1.113 to before 6.1.188Affected
6.6.55 to before 6.6.157Affected

LinuxLinux

6.8Affected
before 6.8Not affected
5.15.221 through 5.15.*Not affected
6.1.188 through 6.1.*Not affected
6.6.157 through 6.6.*Not affected
6.12.110 through 6.12.*Not affected
6.18.51 through 6.18.*Not affected
7.2.5 through 7.2.*Not affected
7.3 and laterNot affected

References

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