CVE-2023-4255: 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 vulne...

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.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS Probability

0.32%

23.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Tats	W3m	0.5.3\+git20230121-1
Tats	W3m	0.5.3\+git20230121-2
Tats	W3m	0.5.3\+git20230129
Fedoraproject	Extra Packages For Enterprise Linux	8.0
Fedoraproject	Fedora	39

References

Timeline

Published: Dec 21, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-4255?

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.

How severe is CVE-2023-4255?

CVE-2023-4255 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.32% probability of exploitation in the next 30 days.

How do I fix CVE-2023-4255?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.