What is CVE-2026-42919?

CVE-2026-42919 is a medium-severity vulnerability in F5 Big-ip, classified under Stack-based Buffer Overflow. CVSS score: 6.7/10. Published 2026-05-13.

How severe is CVE-2026-42919?

Medium severity. CVSS v3 base score is 6.7 out of 10.

Buffer overflow in F5 Big-ip

CVE-2026-42919

A vulnerability exists in BIG-IP systems that may allow an authenticated attacker with administrative access to escalate their privileges. A successful exploit may allow the attacker to cross a security boundary. Note: Software versions…

Vulnerability class: Buffer Overflow

EPSS: 0.001 (23.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.7 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:H.

Affected products

F5 Big-ip — versions 21.1.0, 21.0.0, 17.5.0

Weakness classification (CWE)

CWE-121 — Stack-based Buffer Overflow

References

f5sirt@f5.com (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-42919?: CVE-2026-42919 is a medium-severity vulnerability in F5 Big-ip, classified under Stack-based Buffer Overflow. CVSS score: 6.7/10. Published 2026-05-13.
How severe is CVE-2026-42919?: Medium severity. CVSS v3 base score is 6.7 out of 10.