CVE-2023-53536 blk-crypto: make blk_crypto_evict_key() more robust
A use-after-free vulnerability in the Linux kernel's block crypto subsystem allows attackers to potentially execute code or escalate privileges if specific error conditions occur during key eviction.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53536?
CVE-2023-53536 is a high-severity use after free vulnerability in Linux kernel, published on 4 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
blk-crypto: make blk_crypto_evict_key() more robust
If blk_crypto_evict_key() sees that the key is still in-use (due to a bug) or that ->keyslot_evict failed, it currently just returns while leaving the key linked into the keyslot management structures.
However, blk_crypto_evict_key() is only called in contexts such as inode eviction where failure is not an option. So actually the caller proceeds with freeing the blk_crypto_key regardless of the return value of blk_crypto_evict_key().
These two assumptions don't match, and the result is that there can be a use-after-free in blk_crypto_reprogram_all_keys() after one of these errors occurs. (Note, these errors *shouldn't* happen; we're just talking about what happens if they do anyway.)
Fix this by making blk_crypto_evict_key() unlink the key from the keyslot management structures even on failure.
Also improve some comments.
Weakness: CWE-416
Which versions are affected by CVE-2023-53536?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-53536?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2023-53536 being exploited?
There is no known exploitation of CVE-2023-53536 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-53536, DEBIAN-CVE-2023-53536, GHSA-f2cg-q42r-r6f6, UBUNTU-CVE-2023-53536.