How severe is CVE-2023-4255?

CVE-2023-4255 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2023-4255 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-4255?

CVE-2023-4255 primarily affects Tats W3m. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-4255?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2023-4255 published?

CVE-2023-4255 was published on 2023-12-21 and last updated on 2026-06-17.

CVE-2023-4255

CVE-2023-4255 is a medium-severity vulnerability in Tats W3m with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (24th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Tats W3m
Published: 2023-12-21
Last modified: 2026-06-17

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.

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 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2023-4255 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-4255?: CVE-2023-4255 primarily affects Tats W3m. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-4255?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-4255 published?: CVE-2023-4255 was published on 2023-12-21 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:tats:w3m:0.5.3\+git20230121-1:*:*:*:*:*:*:*
cpe:2.3:a:tats:w3m:0.5.3\+git20230121-2:*:*:*:*:*:*:*
cpe:2.3:a:tats:w3m:0.5.3\+git20230129:*:*:*:*:*:*:*
cpe:2.3:a:fedoraproject:extra_packages_for_enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:39:*:*:*:*:*:*:*

More vulnerabilities in Tats W3m

CVE-2016-9429 — High (CVSS 8.8): An issue was discovered in the Tatsuya Kinoshita w3m fork before 0.5.3-31. Buffer overflow in the formUpdateBuffer…
CVE-2016-9428 — High (CVSS 8.8): An issue was discovered in the Tatsuya Kinoshita w3m fork before 0.5.3-31. Heap-based buffer overflow in the…
CVE-2016-9426 — High (CVSS 8.8): An issue was discovered in the Tatsuya Kinoshita w3m fork before 0.5.3-31. Integer overflow vulnerability in the…
CVE-2016-9425 — High (CVSS 8.8): An issue was discovered in the Tatsuya Kinoshita w3m fork before 0.5.3-31. Heap-based buffer overflow in the…
CVE-2016-9424 — High (CVSS 8.8): An issue was discovered in the Tatsuya Kinoshita w3m fork before 0.5.3-31. w3m doesn't properly validate the value of…
CVE-2016-9423 — High (CVSS 8.8): An issue was discovered in the Tatsuya Kinoshita w3m fork before 0.5.3-31. Heap-based buffer overflow in w3m allows…

All CVEs affecting Tats W3m →

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