A vulnerability exists in NGINX OSS and NGINX Plus when configured to proxy to upstream Transport Layer Security (TLS) servers. An attacker with a man-in-the-middle (MITM) position on the upstream server side—along with conditions beyond the attacker's control—may be able to inject plain text data into the response from an upstream proxied server. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
This vulnerability carries a MEDIUM severity rating with a CVSS v3.1 score of 5.9, indicating it can be exploited remotely over the network but requires specific conditions to be met without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts integrity (unauthorized modifications), for affected systems. Impacting 5 products from f5, from f5, from f5 and 2 others, organizations running these solutions should prioritize assessment and patching.
Reported in 2026, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.
2026-02-04T15:16:14.190
2026-02-13T21:35:01.730
Analyzed
CVSSv3.1: 5.9 (MEDIUM)
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Application | f5 | nginx_gateway_fabric | ≤ 1.6.2 | Yes |
| Application | f5 | nginx_gateway_fabric | < 2.4.1 | Yes |
| Application | f5 | nginx_ingress_controller | ≤ 3.7.2 | Yes |
| Application | f5 | nginx_ingress_controller | ≤ 4.0.1 | Yes |
| Application | f5 | nginx_ingress_controller | < 5.3.3 | Yes |
| Application | f5 | nginx_instance_manager | ≤ 2.21.0 | Yes |
| Application | f5 | nginx_open_source | < 1.28.2 | Yes |
| Application | f5 | nginx_open_source | < 1.29.5 | Yes |
| Application | f5 | nginx_plus | < r35 | Yes |
| Application | f5 | nginx_plus | r32 | Yes |
| Application | f5 | nginx_plus | r32 | Yes |
| Application | f5 | nginx_plus | r32 | Yes |
| Application | f5 | nginx_plus | r32 | Yes |
| Application | f5 | nginx_plus | r33 | Yes |
| Application | f5 | nginx_plus | r33 | Yes |
| Application | f5 | nginx_plus | r33 | Yes |
| Application | f5 | nginx_plus | r34 | Yes |
| Application | f5 | nginx_plus | r34 | Yes |
| Application | f5 | nginx_plus | r35 | Yes |
| Application | f5 | nginx_plus | r36 | Yes |
| Application | f5 | nginx_plus | r36 | Yes |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For f5's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.