What is CVE-2026-40460?

CVE-2026-40460 is a medium-severity vulnerability in F5 Nginx Open Source, classified under Authentication Bypass by Spoofing. CVSS score: 6.5/10. Published 2026-05-13.

How severe is CVE-2026-40460?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in F5 Nginx Open Source

CVE-2026-40460

When NGINX Plus or NGINX Open Source are configured to use the HTTP/3 QUIC module, an attacker may be able to spoof their source IP address allowing for bypass of authorization or bypass of rate limiting. Note: Software versions which hav…

EPSS: 0.000 (8.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L.

Affected products

F5 Nginx Open Source — versions 1.31.0, 1.26.0
F5 Nginx Plus — versions R37, R36, R32

Weakness classification (CWE)

CWE-290 — Authentication Bypass by Spoofing

References

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

Frequently asked questions

What is CVE-2026-40460?: CVE-2026-40460 is a medium-severity vulnerability in F5 Nginx Open Source, classified under Authentication Bypass by Spoofing. CVSS score: 6.5/10. Published 2026-05-13.
How severe is CVE-2026-40460?: Medium severity. CVSS v3 base score is 6.5 out of 10.