What is CVE-2026-5404?

CVE-2026-5404 is a medium-severity vulnerability in Wireshark, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 4.7/10. Published 2026-05-01.

How severe is CVE-2026-5404?

Medium severity. CVSS v3 base score is 4.7 out of 10.

Buffer overflow in Wireshark

CVE-2026-5404

K12 RF5 file parser crash in Wireshark 4.6.0 to 4.6.4 and 4.4.0 to 4.4.14 allows denial of service

Vulnerability class: Buffer Overflow

Published 2026-05-01 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.001 (2.5th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 2.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000

Affected products

Wireshark
Wireshark Foundation — versions 4.6.0, 4.4.0

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

www.wireshark.org/security/wnpa-sec-2026-15.html (Vendor Advisory)
gitlab.com/wireshark/wireshark/-/issues/21094 (issue-tracking, Exploit, permissions-required, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2026-5404?: CVE-2026-5404 is a medium-severity vulnerability in Wireshark, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 4.7/10. Published 2026-05-01.
How severe is CVE-2026-5404?: Medium severity. CVSS v3 base score is 4.7 out of 10.