# CVE-2023-1255: Input buffer over-read in AES-XTS implementation on 64 bit ARM

> An attacker controlling ciphertext size on 64-bit ARM can trigger a buffer over-read in OpenSSL's AES-XTS decryption, causing a denial of service.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 Apr 2023
- **Updated:** 13 Feb 2025
- **Also known as:** ALPINE-CVE-2023-1255, CLEANSTART-2026-MN08707, DEBIAN-CVE-2023-1255, GHSA-4wp2-xw7p-2gfx, JLSEC-2026-238, UBUNTU-CVE-2023-1255

## What is CVE-2023-1255?

CVE-2023-1255 is a medium-severity memory corruption vulnerability in Openssl Openssl, published on 20 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Issue summary: The AES-XTS cipher decryption implementation for 64 bit ARM
platform contains a bug that could cause it to read past the input buffer,
leading to a crash.

Impact summary: Applications that use the AES-XTS algorithm on the 64 bit ARM
platform can crash in rare circumstances. The AES-XTS algorithm is usually
used for disk encryption.

The AES-XTS cipher decryption implementation for 64 bit ARM platform will read
past the end of the ciphertext buffer if the ciphertext size is 4 mod 5 in 16
byte blocks, e.g. 144 bytes or 1024 bytes. If the memory after the ciphertext
buffer is unmapped, this will trigger a crash which results in a denial of
service.

If an attacker can control the size and location of the ciphertext buffer
being decrypted by an application using AES-XTS on 64 bit ARM, the
application is affected. This is fairly unlikely making this issue
a Low severity one.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2023-1255?

It affects 1 product.


Products: Openssl Openssl.

## How do I fix CVE-2023-1255?

Apply the vendor's patch.

## Is CVE-2023-1255 being exploited?

There is no known exploitation of CVE-2023-1255 in the wild and no public exploit code.

## Other vulnerabilities in Openssl Openssl

- [CVE-2009-3245](https://insights.sbomify.com/CVE-2009-3245/): Null dereference in n/a (critical 10.0)
- [CVE-2006-3738](https://insights.sbomify.com/CVE-2006-3738/): Memory corruption in n/a (critical 10.0)
- [CVE-2026-63073](https://insights.sbomify.com/CVE-2026-63073/): Untrusted Sender DN Used as Format String in CMP Response Validation (critical 9.8)
- [CVE-2016-6309](https://insights.sbomify.com/CVE-2016-6309/): Use after free in n/a (critical 9.8)
- [CVE-2016-0799](https://insights.sbomify.com/CVE-2016-0799/): Integer overflow in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-1255 and fix it if it is affected.

What it is: CVE-2023-1255 is a medium-severity memory corruption vulnerability in Openssl Openssl, published on 20 Apr 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-1255 in the wild and no public exploit code.

Affected product: Openssl Openssl. 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-2023-1255/ (Markdown: https://insights.sbomify.com/CVE-2023-1255/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-1255
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-1255
- OSV: https://osv.dev/vulnerability/CVE-2023-1255

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-1255/
Summaries are generated and may contain mistakes; the official description above is the record.