CVE-2024-41051: cachefiles: wait for ondemand_object_worker to finish when dropping object

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-29 · updated 2026-08-04
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: cachefiles: wait for ondemand_object_worker to finish when dropping object When queuing ondemand_object_worker() to re-open the object, cachefiles_object is not pinned. The cachefiles_object may be freed when the pending read request is completed intentionally and the related erofs is umounted. If ondemand_object_worker() runs after the object is freed, it will incur use-after-free problem as shown below. process A processs B process C process D cachefiles_ondemand_send_req() // send a read req X // wait for its completion // close ondemand fd cachefiles_ondemand_fd_release() // set object as CLOSE cachefiles_ondemand_daemon_read() // set object as REOPENING queue_work(fscache_wq, &info->ondemand_work) // close /dev/cachefiles cachefiles_daemon_release cachefiles_flush_reqs complete(&req->done) // read req X is completed // umount the erofs fs cachefiles_put_object() // object will be freed cachefiles_ondemand_deinit_obj_info() kmem_cache_free(object) // both info and object are freed ondemand_object_worker() When dropping an object, it is no longer necessary to reopen the object, so use cancel_work_sync() to cancel or wait for ondemand_object_worker() to finish.

Affected products

Linux kernel: from 6.1.95 before 6.1.100; from 6.6.35 before 6.6.41; from 6.8 before 6.9.10; 6.10-rc1, 6.10-rc2, 6.10-rc3, 6.10-rc4, 6.10-rc5, 6.10-rc6 (+1) — fixed in 6.1.100, 6.6.41, 6.9.10

How to fix

Upgrade to a fixed version: Linux kernel 6.1.100, 6.6.41, 6.9.10. Check the vendor advisory for mitigations.

References

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