# CVE-2023-4255: w3m: An out-of-bounds write issue has been discovered in the backspace handling of the checkType() function in etc.c withi...

CVE-2023-4255 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2023-4255, released December 21, 2023. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2023-4255
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0032
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 21, 2023

## Description

An out-of-bounds write issue has been discovered in the backspace handling of the checkType() function in etc.c within the W3M application. This vulnerability is triggered by supplying a specially crafted HTML file to the w3m binary. Exploitation of this flaw could lead to application crashes, resulting in a denial of service condition.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | w3m Debian 13.5 (trixie) | 0.5.3+git20230121-2.1 | [DEBIAN-CVE-2023-4255](https://patchblox.com/security/data/fix/linux/debian-cve-2023-4255.md) | Dec 21, 2023 |
| Linux | w3m Debian 14 | 0.5.3+git20230121-2.1 | [DEBIAN-CVE-2023-4255](https://patchblox.com/security/data/fix/linux/debian-cve-2023-4255.md) | Dec 21, 2023 |
| Linux | w3m Ubuntu 18.04.6 LTS (bionic) | 0.5.3-36ubuntu0.1+esm1 | [w3m 0.5.3-36ubuntu0.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-w3m-0.5.3-36ubuntu0.1-esm1.md) | Jan 1, 2024 |
| Linux | w3m Ubuntu 20.04 LTS (focal) | 0.5.3-37ubuntu0.2 | [w3m 0.5.3-37ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-w3m-0.5.3-37ubuntu0.2.md) | Jan 1, 2024 |
| Linux | w3m Ubuntu 22.04.1 LTS (jammy) | 0.5.3+git20210102-6ubuntu0.2 | [w3m 0.5.3+git20210102-6ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-w3m-0.5.3-git20210102-6ubuntu0.2.md) | Jan 1, 2024 |
| Linux | w3m Ubuntu 24.04.5 LTS (noble) | 0.5.3+git20230121-2ubuntu1 | [w3m 0.5.3+git20230121-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-w3m-0.5.3-git20230121-2ubuntu1.md) | Jan 1, 2024 |
| Linux | w3m Ubuntu 24.10 (oracular) | 0.5.3+git20230121-2ubuntu1 | [w3m 0.5.3+git20230121-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-w3m-0.5.3-git20230121-2ubuntu1.md) | Jan 2, 2024 |
| Linux | w3m Ubuntu 25.04 (plucky) | 0.5.3+git20230121-2ubuntu1 | [w3m 0.5.3+git20230121-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-w3m-0.5.3-git20230121-2ubuntu1.md) | Jan 2, 2024 |
| Linux | w3m-img Ubuntu 18.04.6 LTS (bionic) | 0.5.3-36ubuntu0.1+esm1 | [w3m-img 0.5.3-36ubuntu0.1+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-w3m-img-0.5.3-36ubuntu0.1-esm1.md) | Jan 1, 2024 |
| Linux | w3m-img Ubuntu 20.04 LTS (focal) | 0.5.3-37ubuntu0.2 | [w3m-img 0.5.3-37ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-focal-w3m-img-0.5.3-37ubuntu0.2.md) | Jan 1, 2024 |
| Linux | w3m-img Ubuntu 22.04.1 LTS (jammy) | 0.5.3+git20210102-6ubuntu0.2 | [w3m-img 0.5.3+git20210102-6ubuntu0.2](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-w3m-img-0.5.3-git20210102-6ubuntu0.2.md) | Jan 1, 2024 |
| Linux | w3m-img Ubuntu 24.04.5 LTS (noble) | 0.5.3+git20230121-2ubuntu1 | [w3m-img 0.5.3+git20230121-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-w3m-img-0.5.3-git20230121-2ubuntu1.md) | Jan 1, 2024 |
| Linux | w3m-img Ubuntu 24.10 (oracular) | 0.5.3+git20230121-2ubuntu1 | [w3m-img 0.5.3+git20230121-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-oracular-w3m-img-0.5.3-git20230121-2ubuntu1.md) | Jan 2, 2024 |
| Linux | w3m-img Ubuntu 25.04 (plucky) | 0.5.3+git20230121-2ubuntu1 | [w3m-img 0.5.3+git20230121-2ubuntu1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-w3m-img-0.5.3-git20230121-2ubuntu1.md) | Jan 2, 2024 |

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Data as of 2026-11-08T00:53:09Z 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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