Threat Intelligence / CVE / CVE-2026-11311

CVE-2026-11311 — F5 NGINX Gateway Fabric

CVSS v3.1 8.1 (HIGH) · CVSS v4.0 8.6 · EPSS 0.5% (higher than 43.7% of all scored CVEs) · Priority 5.8/10 · Published 2026-06-17

As of 2026-06-17, CVE-2026-11311 is a HIGH-severity vulnerability in F5 NGINX Gateway Fabric, CVSS v3.1 8.1, EPSS 0.5% (43.7th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-11311, most recently “F5 Out-of-Band Patches for Critical NGINX HTTP/3 Use-After-Free and Proxy/gRPC Heap Overflow (CVE-2026-42530, CVE-2026-42055) plus NGINX Gateway Fabric Config Injection (CVE-2026-11311, CVE-2026-50107)”.

Last updated: 2026-06-17

What is CVE-2026-11311?

When NGINX Plus is configured as the data plane for NGINX Gateway Fabric, an injection vulnerability exists in the NGINX configuration generator component of NGINX Gateway Fabric. User-supplied string values from the NginxProxy Custom Resource Definition serverTokens field and the AuthenticationFilter Custom Resource Definition extraAuthArgs field are rendered directly into NGINX configuration templates without sanitization or escaping. An authenticated attacker with permission to create or modify these Custom Resource Definitions may craft values that inject arbitrary NGINX configuration directives. This is a control plane issue; there is no data plane exposure from the vulnerability trigger itself. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

The record classifies CVE-2026-11311 under weakness class CWE-76. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 87 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 8.1 — HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CVSS v4.0 base score: 8.6
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
EPSS (FIRST): 0.5% probability of exploitation in the next 30 days, higher than 43.7% of all scored CVEs
CISA KEV: Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority: 5.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published: 2026-06-17

Is CVE-2026-11311 being exploited?

No public exploitation evidence for CVE-2026-11311 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-06-17. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited.

Affected products and versions

F5: NGINX Gateway Fabric

How to fix CVE-2026-11311

No vendor patch reference has been recorded for CVE-2026-11311 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-11311

1 tracked threat in the Threadlinqs corpus references CVE-2026-11311, either in the campaign’s CVE list or as an indicator on the campaign record.

F5 Out-of-Band Patches for Critical NGINX HTTP/3 Use-After-Free and Proxy/gRPC Heap Overflow (CVE-2026-42530, CVE-2026-42055) plus NGINX Gateway Fabric Config Injection (CVE-2026-11311, CVE-2026-50107) — CRITICAL · 2026-06-18

Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-06-25. This product uses the NVD API but is not endorsed or certified by the NVD.

Vendor advisory and patch

my.f5.com — vendor advisory

Full detection coverage & IOCs for threats exploiting CVE-2026-11311 are available via the Threadlinqs MCP server (Purple tier). View plans →

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