VDB-363559 · CVE-2026-40460 · K000161068

F5 NGINX Plus/NGINX Open Source Source IP Address authentication spoofing

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.8	$0-$5k	0.00

Summaryinfo

A vulnerability was found in F5 NGINX Plus and NGINX Open Source. It has been rated as critical. This impacts an unknown function of the component Source IP Address Handler. This manipulation causes authentication spoofing. The identification of this vulnerability is CVE-2026-40460. It is possible to initiate the attack remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in F5 NGINX Plus and NGINX Open Source (version unknown) and classified as critical. Affected by this vulnerability is an unknown function of the component Source IP Address Handler. The manipulation with an unknown input leads to a authentication spoofing vulnerability. The CWE definition for the vulnerability is CWE-290. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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 have reached End of Technical Support (EoTS) are not evaluated.

It is possible to read the advisory at my.f5.com. This vulnerability is known as CVE-2026-40460 since 05/01/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 314992 (Fedora 42 : nginx / nginx-mod-brotli / nginx-mod-fancyindex / etc (2026-38623b4fed)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (314992) and CERT Bund (WID-SEC-2026-1527). Be aware that VulDB is the high quality source for vulnerability data.

Affected

Debian Linux
Amazon Linux 2
Red Hat Enterprise Linux
Fedora Linux
Ubuntu Linux
Oracle Linux
SUSE openSUSE
RESF Rocky Linux
NGINX NGINX Plus
NGINX NGINX
SUSE Linux

Productinfo

Type

Web Server

Vendor

Name

License

commercial

Website

Vendor: https://f5.com/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 6.9
VulDB Meta Temp Score: 6.8

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 6.5
CNA Vector: 🔒

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Authentication spoofing
CWE: CWE-290 / CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 314992
Nessus Name: Fedora 42 : nginx / nginx-mod-brotli / nginx-mod-fancyindex / etc (2026-38623b4fed)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Timelineinfo

05/01/2026 CVE reserved
05/13/2026 +12 days Advisory disclosed
05/13/2026 +0 days VulDB entry created
06/30/2026 +48 days VulDB entry last update

Sourcesinfo

Vendor: f5.com

Advisory: K000161068
Status: Confirmed

CVE: CVE-2026-40460 (🔒)
GCVE (CVE): GCVE-0-2026-40460
GCVE (VulDB): GCVE-100-363559
CERT Bund: WID-SEC-2026-1527 - NGINX Open Source and NGINX Plus: Mehrere Schwachstellen

Entryinfo

Created: 05/13/2026 17:41
Updated: 06/30/2026 16:02
Changes: 05/13/2026 17:41 (75), 05/15/2026 21:18 (7), 05/16/2026 10:02 (2), 06/30/2026 16:02 (1)
Complete: 🔍
Cache ID: 216::103