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GHSA-8RXJ-RXX8-XJ47

Vulnerability from github – Published: 2026-10-14 15:32 – Updated: 2026-10-14 15:32

Details

Description

NGINX Gateway Fabric has a vulnerability when it renders the spec.basic.realm (and spec.jwt.realm) field of a namespaced AuthenticationFilter verbatim, unescaped and unvalidated, into the shared data-plane nginx.conf as auth_basic "";. A namespaced authenticated attacker that configures AuthenticationFilter CRD to an HTTPRoute/GRPCRoute on a shared Gateway can craft a realm value that closes the quoted directive and the enclosing location {} block and injects arbitrary NGINX directives into that Gateway's data-plane config.

Impact

A remote authenticated attacker can send crafted requests to configure NGINX Gateway Fabric AuthenticationFilter CRD and may be able to read every co-located tenant's mounted secrets, SSRF via proxy_pass, reading the pod ServiceAccount token, or hijacking other tenants' routes. There is no data plane exposure; this is a control plane issue only.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Severity

8.8 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

8.7 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-91184"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-76"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-14T15:17:26Z",
    "severity": "HIGH"
  },
  "details": "Description\n\nNGINX Gateway Fabric\u00a0has a vulnerability when it renders the spec.basic.realm (and spec.jwt.realm) field of a namespaced AuthenticationFilter verbatim, unescaped and unvalidated, into the shared data-plane nginx.conf as auth_basic \"\u003crealm\u003e\";. A namespaced authenticated attacker that configures AuthenticationFilter CRD to an HTTPRoute/GRPCRoute on a shared Gateway can craft a realm value that closes the quoted directive and the enclosing location {} block and injects arbitrary NGINX directives into that Gateway\u0027s data-plane config.\u00a0\n\nImpact\n\nA remote authenticated attacker can send crafted requests to configure NGINX Gateway Fabric\u00a0AuthenticationFilter CRD and\u00a0may be able to read every co-located tenant\u0027s mounted secrets, SSRF via proxy_pass, reading the pod ServiceAccount token, or hijacking other tenants\u0027 routes.\u00a0There is no data plane exposure; this is a control plane issue only.\n\n\n\n\n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated.",
  "id": "GHSA-8rxj-rxx8-xj47",
  "modified": "2026-10-14T15:32:30Z",
  "published": "2026-10-14T15:32:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91184"
    },
    {
      "type": "WEB",
      "url": "https://my.f5.com/manage/s/article/K000162609"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-91184 (GCVE-0-2026-91184)

Vulnerability from cvelistv5 – Published: 2026-10-14 14:40 – Updated: 2026-10-14 14:40

Title

NGINX Gateway Fabric vulnerability

Summary

Description NGINX Gateway Fabric has a vulnerability when it renders the spec.basic.realm (and spec.jwt.realm) field of a namespaced AuthenticationFilter verbatim, unescaped and unvalidated, into the shared data-plane nginx.conf as auth_basic "<realm>";. A namespaced authenticated attacker that configures AuthenticationFilter CRD to an HTTPRoute/GRPCRoute on a shared Gateway can craft a realm value that closes the quoted directive and the enclosing location {} block and injects arbitrary NGINX directives into that Gateway's data-plane config. Impact A remote authenticated attacker can send crafted requests to configure NGINX Gateway Fabric AuthenticationFilter CRD and may be able to read every co-located tenant's mounted secrets, SSRF via proxy_pass, reading the pod ServiceAccount token, or hijacking other tenants' routes. There is no data plane exposure; this is a control plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CWE

CWE-76

Assigner

f5 CNA under the mitre root

CNA scorecard B 84/100 over 87 records in the last 180 days details

References

1 reference

URL	Tags
https://my.f5.com/manage/s/article/K000162609	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
F5	NGINX Gateway Fabric	Affected: 2.4.0 , < 2.8.0 (custom)

Date Public

2023-01-01 00:00

Credits

F5 acknowledges apvxlab (AppViewX security research) for bringing this issue to our attention and following the highest standards of coordinated disclosure.

Show details on NVD website

JSON

To clipboard

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  "containers": {
    "cna": {
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          "defaultStatus": "unknown",
          "modules": [
            "NGF"
          ],
          "product": "NGINX Gateway Fabric",
          "vendor": "F5",
          "versions": [
            {
              "lessThan": "2.8.0",
              "status": "affected",
              "version": "2.4.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
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          "value": "F5 acknowledges apvxlab (AppViewX security research) for bringing this issue to our attention and following the highest standards of coordinated disclosure."
        }
      ],
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              "value": "Description\u003cbr\u003e\u003cbr\u003eNGINX Gateway Fabric\u0026nbsp;has a vulnerability when it renders the spec.basic.realm (and spec.jwt.realm) field of a namespaced AuthenticationFilter verbatim, unescaped and unvalidated, into the shared data-plane nginx.conf as auth_basic \"\u0026lt;realm\u0026gt;\";. A namespaced authenticated attacker that configures AuthenticationFilter CRD to an HTTPRoute/GRPCRoute on a shared Gateway can craft a realm value that closes the quoted directive and the enclosing location {} block and injects arbitrary NGINX directives into that Gateway\u0027s data-plane config.\u0026nbsp;\u003cbr\u003e\u003cbr\u003eImpact\u003cbr\u003e\u003cbr\u003eA remote authenticated attacker can send crafted requests to configure NGINX Gateway Fabric\u0026nbsp;AuthenticationFilter CRD and\u0026nbsp;may be able to read every co-located tenant\u0027s mounted secrets, SSRF via proxy_pass, reading the pod ServiceAccount token, or hijacking other tenants\u0027 routes.\u0026nbsp;\u003cspan style=\"background-color: rgb(255, 255, 255);\"\u003eThere is no data plane exposure; this is a control plane issue only.\u003c/span\u003e\n\n\u003cbr\u003e\u003cbr\u003e\n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated."
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      ],
      "impacts": [
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          "capecId": "CAPEC-3",
          "descriptions": [
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      "metrics": [
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          "cvssV3_1": {
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          "scenarios": [
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        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
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            "Safety": "NOT_DEFINED",
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            "baseScore": 8.7,
            "baseSeverity": "HIGH",
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      "providerMetadata": {
        "dateUpdated": "2026-10-14T14:40:27.849Z",
        "orgId": "9dacffd4-cb11-413f-8451-fbbfd4ddc0ab",
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            }
          ],
          "value": "As this attack is conducted by authenticated users with Kubernetes Role-based Access Control (RBAC) write access to AuthenticationFilter\u00a0CRD\u00a0and Secrets, the only complete mitigation is to restrict that access to fully trusted administrators only."
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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