# CVE-2023-53713: arm64: sme: Use STR P to clear FFR context field in streaming SVE mode

> A memory corruption flaw in the Linux kernel's ARM64 SME implementation allows attackers to corrupt adjacent memory, potentially causing crashes or code execution.

- **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:** 22 Oct 2025
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2023-53713, DEBIAN-CVE-2023-53713, GHSA-f5qp-mjwc-27gf, UBUNTU-CVE-2023-53713

## What is CVE-2023-53713?

CVE-2023-53713 is a high-severity memory corruption vulnerability in Linux, published on 22 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:

arm64: sme: Use STR P to clear FFR context field in streaming SVE mode

The FFR is a predicate register which can vary between 16 and 256 bits
in size depending upon the configured vector length. When saving the
SVE state in streaming SVE mode, the FFR register is inaccessible and
so commit 9f5848665788 ("arm64/sve: Make access to FFR optional") simply
clears the FFR field of the in-memory context structure. Unfortunately,
it achieves this using an unconditional 8-byte store and so if the SME
vector length is anything other than 64 bytes in size we will either
fail to clear the entire field or, worse, we will corrupt memory
immediately following the structure. This has led to intermittent kfence
splats in CI [1] and can trigger kmalloc Redzone corruption messages
when running the 'fp-stress' kselftest:

 | =============================================================================
 | BUG kmalloc-1k (Not tainted): kmalloc Redzone overwritten
 | -----------------------------------------------------------------------------
 |
 | 0xffff000809bf1e22-0xffff000809bf1e27 @offset=7714. First byte 0x0 instead of 0xcc
 | Allocated in do_sme_acc+0x9c/0x220 age=2613 cpu=1 pid=531
 |  __kmalloc+0x8c/0xcc
 |  do_sme_acc+0x9c/0x220
 |  ...

Replace the 8-byte store with a store of a predicate register which has
been zero-initialised with PFALSE, ensuring that the entire field is
cleared in memory.

[1] https://lore.kernel.org/r/CA+G9fYtU7HsV0R0dp4XEH5xXHSJFw8KyDf5VQrLLfMxWfxQkag@mail.gmail.com

## Which versions are affected by CVE-2023-53713?


## How do I fix CVE-2023-53713?

Apply the vendor's patch.

## Is CVE-2023-53713 being exploited?

There is no known exploitation of CVE-2023-53713 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-53713 and fix it if it is affected.

What it is: CVE-2023-53713 is a high-severity memory corruption vulnerability in Linux, published on 22 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-2023-53713 in the wild and no public exploit code.

Affected product: Linux. 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-2023-53713/ (Markdown: https://insights.sbomify.com/CVE-2023-53713/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53713
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53713
- OSV: https://osv.dev/vulnerability/CVE-2023-53713

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53713/
Summaries are generated and may contain mistakes; the official description above is the record.