What is CVE-2026-42530?

CVE-2026-42530 is a high-severity vulnerability in F5 Nginx Open Source, classified under Use After Free. CVSS score: 8.1/10. Published 2026-06-17.

How severe is CVE-2026-42530?

High severity. CVSS v3 base score is 8.1 out of 10.

Use After Free in F5 Nginx Open Source

CVE-2026-42530

NGINX Open Source has a vulnerability in the ngx_http_v3_module module. When NGINX Open Source is configured to use the HTTP/3 QUIC module, a remote unauthenticated attacker along with conditions beyond their control can use a specially cr…

Vulnerability class: Use-After-Free

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

F5 Nginx Open Source — versions 1.31.0

Weakness classification (CWE)

CWE-416 — Use After Free

References

f5sirt@f5.com (vendor-advisory)

Frequently asked questions

What is CVE-2026-42530?: CVE-2026-42530 is a high-severity vulnerability in F5 Nginx Open Source, classified under Use After Free. CVSS score: 8.1/10. Published 2026-06-17.
How severe is CVE-2026-42530?: High severity. CVSS v3 base score is 8.1 out of 10.