Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| F5 | Nginx Gateway Fabric | >= 1.2.0, <= 1.6.2 |
| F5 | Nginx Ingress Controller | >= 3.4.0, <= 3.7.2 |
| F5 | Nginx Instance Manager | >= 2.15.1, <= 2.21.0 |
| F5 | Nginx Open Source | >= 1.3.0, < 1.28.2 |
| F5 | Nginx Plus | >= r33, < r35 |
Related Weaknesses (CWE)
References
- https://my.f5.com/manage/s/article/K000159824Vendor Advisory
- http://www.openwall.com/lists/oss-security/2026/02/05/1Mailing ListThird Party Advisory
FAQ
What is CVE-2026-1642?
CVE-2026-1642 is a vulnerability with a CVSS score of 5.9 (MEDIUM). 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 ser...
How severe is CVE-2026-1642?
CVE-2026-1642 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-1642?
Check the references section above for vendor advisories and patch information. Affected products include: F5 Nginx Gateway Fabric, F5 Nginx Ingress Controller, F5 Nginx Instance Manager, F5 Nginx Open Source, F5 Nginx Plus.