#VU84908 Out-of-bounds write in w3m - CVE-2023-4255

Vulnerability identifier: #VU84908

Vulnerability risk: High

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2023-4255

CWE-ID: CWE-787

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
w3m
Server applications / Web servers

Vendor: w3m.sourceforge.net

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a boundary error when processing untrusted input within the checkType() function in etc.c. A remote attacker can create a specially crafted HTML file, trick the victim into opening it using the affected software, trigger an out-of-bounds write and execute arbitrary code on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

w3m: 0.5.3+git20220429 - 0.5.3+git20230121

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External links
https://bugzilla.redhat.com/show_bug.cgi?id=2255207
https://github.com/tats/w3m/commit/edc602651c506aeeb60544b55534dd1722a340d3
https://github.com/tats/w3m/issues/268
https://github.com/tats/w3m/pull/273

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.