# 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.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 4 Oct 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-53536, DEBIAN-CVE-2023-53536, GHSA-f2cg-q42r-r6f6, UBUNTU-CVE-2023-53536

## 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 (Use After Free)

## Which versions are affected by CVE-2023-53536?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-53536?

Apply the vendor's patch.

## 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

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-53536 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2023-53536 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-53536/ (Markdown: https://insights.sbomify.com/CVE-2023-53536/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53536
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53536
- OSV: https://osv.dev/vulnerability/CVE-2023-53536

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53536/
Summaries are generated and may contain mistakes; the official description above is the record.