NGINX Ingress Controller: Authentication Bypass by Spoofing
CVE-2026-94197 is a high-severity authentication bypass by spoofing vulnerability in NGINX Ingress Controller from F5, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 5.7.0 as the first without the flaw, so updating NGINX Ingress Controller to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.39% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update NGINX Ingress Controller to 5.7.0 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| F5 | NGINX Ingress Controller | 5.5.0 up to, but not including, 5.7.0 | 5.7.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CNA (f5.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (f5.com) |
| CVSS 3.1 | 7.5 | High | CNA (f5.com) |
Official description
An authentication and authorization bypass vulnerability exists in F5 NGINX Kubernetes Ingress Controller (NIC) when configured with the `ExternalAuth` policy or Ingress external authentication. Client-supplied X-Forwarded-Prefix, X-Forwarded-URI, X-Original-URI, and X-Forwarded-Method routing and method headers are forwarded unsanitized into the internal authentication subrequest (handled by the NGINX auth_request directive). As a result, an unauthenticated, remote attacker may spoof request attributes evaluated by the external authentication provider. Impact: This vulnerability may allow remote attackers unauthenticated access to protected paths. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass by Spoofing
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
More Authentication Bypass by Spoofing vulnerabilities (CWE-290)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in NGINX Ingress Controller
- 7.5 High severity
- 8.3 High severity
- 8.2 High severity
- 8.3 High severity
- 8.1 High severity
- 8.1 High severity
Recent Authentication Bypass by Spoofing vulnerabilities
- 8.1 High severity
- 9.3 Critical severity
- 8.6 High severity
- 9.4 Critical severity
- 7.5 High severity
- 7.5 High severity
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