module/dups: Fix use-after-free in kmod_dup_req lifetime handling

Summary

In the Linux kernel, the following vulnerability has been resolved: module/dups: Fix use-after-free in kmod_dup_req lifetime handling The kmod dups code uses RCU to ensure that a kmod_dup_req instance is freed only after it is no longer referenced. When releasing an instance, the kmod_dup_request_delete() function removes the kmod_dup_req from the dup_kmod_reqs list, waits via synchronize_rcu() and finally frees it. However, this doesn't work correctly because parallel users referencing the instance in kmod_dup_request_exists_wait() don't enter an RCU read-side critical section. This can result in a use-after-free. The kmod_dup_request_exists_wait() function may need to hold a valid reference to a kmod_dup_req instance across a blocking wait until the corresponding modprobe command completes. This makes it unsuitable for RCU. Fix the issue by changing the lifecycle management of kmod_dup_req to use reference counting.

Timeline

1. Sep 17, 2026, 4:08 PM UTCCVE published
2. Oct 21, 2026, 12:50 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 8660484ed1cf3261e89e0bad94c6395597e87599 · fixed in a3205bd1f218053575589b14caf8df667f344134; From 8660484ed1cf3261e89e0bad94c6395597e87599 · fixed in 2c85e0fb528e039aa8ea1e9c2a1f64347f990541; From 8660484ed1cf3261e89e0bad94c6395597e87599 · fixed in b2709aad7599f6fd957939b60f4a8323c8f08072; From 8660484ed1cf3261e89e0bad94c6395597e87599 · fixed in cd2396fc9684d2cfd3f3c3f09c79d6d9d725b0ca; From 8660484ed1cf3261e89e0bad94c6395597e87599 · fixed in 5eecb11b543f9f417bcf0dea239ff99c6af65dbd

• Linux Linux

  6.4

• KernelLinux

  From 6.4.0 · fixed in 6.6.160; From 6.7.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.52; From 6.19.0 · fixed in 7.2.6

References 5