cachefiles: Fix NULL pointer dereference in object->file

Summary

In the Linux kernel, the following vulnerability has been resolved: cachefiles: Fix NULL pointer dereference in object->file At present, the object->file has the NULL pointer dereference problem in ondemand-mode. The root cause is that the allocated fd and object->file lifetime are inconsistent, and the user-space invocation to anon_fd uses object->file. Following is the process that triggers the issue: [write fd] [umount] cachefiles_ondemand_fd_write_iter fscache_cookie_state_machine cachefiles_withdraw_cookie if (!file) return -ENOBUFS cachefiles_clean_up_object cachefiles_unmark_inode_in_use fput(object->file) object->file = NULL // file NULL pointer dereference! __cachefiles_write(..., file, ...) Fix this issue by add an additional reference count to the object->file before write/llseek, and decrement after it finished.

Timeline

1. Dec 27, 2024, 2:11 PM UTCCVE published
2. Oct 15, 2026, 9:41 PM UTCCISA SSVC assessment

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

3. Oct 15, 2026, 9:41 PM UTCRecord last updated

Affected versions

• Linux Linux

  From c8383054506c77b814489c09877b5db83fd4abf2 · fixed in d6bba3ece960129a553d4b16f1b00c884dc0993a; From c8383054506c77b814489c09877b5db83fd4abf2 · fixed in 785408bbafcfa24c9fc5b251f03fd0780ce182bd; From c8383054506c77b814489c09877b5db83fd4abf2 · fixed in f98770440c9bc468e2fd878212ec9526dbe08293; From c8383054506c77b814489c09877b5db83fd4abf2 · fixed in 9582c7664103c9043e80a78f5c382aa6bdd67418; From c8383054506c77b814489c09877b5db83fd4abf2 · fixed in 31ad74b20227ce6b40910ff78b1c604e42975cf1

• Linux Linux

  5.19

• KernelLinux

  From 5.19.0 · fixed in 6.1.129; From 6.2.0 · fixed in 6.6.78; From 6.7.0 · fixed in 6.11.11; From 6.12.0 · fixed in 6.12.2

References 5