# CVE-2023-34256: linux: An issue was discovered in the Linux kernel before 6.3.3

CVE-2023-34256 is fixed in 20 products on 1 platform, first by ALAS2023-2023-184, released May 25, 2023. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2023-34256
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0025
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 25, 2023

## Description

An issue was discovered in the Linux kernel before 6.3.3. There is an out-of-bounds read in crc16 in lib/crc16.c when called from fs/ext4/super.c because ext4_group_desc_csum does not properly check an offset. NOTE: this is disputed by third parties because the kernel is not intended to defend against attackers with the stated "When modifying the block device while it is mounted by the filesystem" access.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | bpftool amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | bpftool-debuginfo amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-debuginfo amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-debuginfo-common-aarch64 amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-debuginfo-common-x86_64 amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-devel amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-headers amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-libbpf amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-libbpf-devel amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-libbpf-static amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-livepatch-6.1.29-47.49 amzn 2023 | 1.0-0.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-tools amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-tools-debuginfo amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | kernel-tools-devel amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | linux Debian 12.15 (bookworm) | 6.1.37-1 | [DEBIAN-CVE-2023-34256](https://patchblox.com/security/data/fix/linux/debian-cve-2023-34256.md) | May 31, 2023 |
| Linux | linux Debian 13.5 (trixie) | 6.3.7-1 | [DEBIAN-CVE-2023-34256](https://patchblox.com/security/data/fix/linux/debian-cve-2023-34256.md) | May 31, 2023 |
| Linux | linux Debian 14 | 6.3.7-1 | [DEBIAN-CVE-2023-34256](https://patchblox.com/security/data/fix/linux/debian-cve-2023-34256.md) | May 31, 2023 |
| Linux | perf amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | perf-debuginfo amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | python3-perf amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |
| Linux | python3-perf-debuginfo amzn 2023 | 6.1.29-47.49.amzn2023 | [ALAS2023-2023-184](https://patchblox.com/security/data/fix/linux/alas2023-2023-184.md) | May 25, 2023 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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