CVE-2023-53810
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-12-09

Last updated on: 2025-12-09

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: blk-mq: release crypto keyslot before reporting I/O complete Once all I/O using a blk_crypto_key has completed, filesystems can call blk_crypto_evict_key(). However, the block layer currently doesn't call blk_crypto_put_keyslot() until the request is being freed, which happens after upper layers have been told (via bio_endio()) the I/O has completed. This causes a race condition where blk_crypto_evict_key() can see 'slot_refs != 0' without there being an actual bug. This makes __blk_crypto_evict_key() hit the 'WARN_ON_ONCE(atomic_read(&slot->slot_refs) != 0)' and return without doing anything, eventually causing a use-after-free in blk_crypto_reprogram_all_keys(). (This is a very rare bug and has only been seen when per-file keys are being used with fscrypt.) There are two options to fix this: either release the keyslot before bio_endio() is called on the request's last bio, or make __blk_crypto_evict_key() ignore slot_refs. Let's go with the first solution, since it preserves the ability to report bugs (via WARN_ON_ONCE) where a key is evicted while still in-use.
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Meta Information
Published
2025-12-09
Last Modified
2025-12-09
Generated
2026-05-07
AI Q&A
2025-12-09
EPSS Evaluated
2026-05-05
NVD
CVE-2023-53810
EUVD
EUVD-2023-60096
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability in the Linux kernel's block layer involves a race condition related to the handling of crypto keyslots used for disk encryption. Specifically, the kernel delays releasing a crypto keyslot until after the I/O request is reported as complete to upper layers. This timing allows a function that evicts keys to see the keyslot as still in use, triggering a warning and skipping the eviction. This can eventually lead to a rare use-after-free bug when per-file encryption keys are used, potentially causing memory safety issues.


How can this vulnerability impact me? :

The vulnerability can cause a rare use-after-free condition in the kernel when using per-file encryption keys, which may lead to memory corruption or instability in the system. This could potentially be exploited to cause crashes or other unintended behavior in the kernel, affecting system reliability and security.


What immediate steps should I take to mitigate this vulnerability?

To mitigate this vulnerability, update your Linux kernel to a version that includes the fix where the blk_crypto_keyslot is released before bio_endio() is called on the request's last bio. This prevents the race condition and use-after-free issue. Since this is a kernel-level fix, applying the latest kernel patches or updates from your Linux distribution is the recommended immediate step.


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