Vulnerability-Lookup

FKIE_CVE-2026-42055

Vulnerability from fkie_nvd - Published: 2026-06-17 15:16 - Updated: 2026-08-11 15:12

Severity

8.1 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and ngx_http_grpc_module modules. This vulnerability exists when the proxy_http_version to 2 or grpc_pass directives are used to proxy HTTP/2 traffic, the ignore_invalid_headers directive is set to off, and the large_client_header_buffers directive size is larger than 2 megabytes. A remote, unauthenticated attacker, along with conditions beyond their control, could send large headers while creating an upstream request. This may cause a heap-based buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

References

URL	Tags
f5sirt@f5.com	https://my.f5.com/manage/s/article/K000161584	Vendor Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:27197	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:36331	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:36364	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:36618	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:36639	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:38847	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:44481	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/errata/RHSA-2026:46836	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://access.redhat.com/security/cve/CVE-2026-42055	Third Party Advisory
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://bugzilla.redhat.com/show_bug.cgi?id=2489866	Third Party Advisory, Issue Tracking
0b0ca135-0b70-47e7-9f44-1890c2a1c46c	https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42055.json	Third Party Advisory

Impacted products

Vendor	Product	Version
f5	dos	*
f5	dos	4.9.0
f5	nginx_gateway_fabric	*
f5	nginx_gateway_fabric	*
f5	nginx_ingress_controller	*
f5	nginx_ingress_controller	*
f5	nginx_ingress_controller	*
f5	nginx_instance_manager	*
f5	nginx_open_source	*
f5	nginx_open_source	*
f5	nginx_plus	*
f5	nginx_plus	*
f5	nginx_plus	r36
f5	nginx_plus	r36
f5	nginx_plus	r36
f5	nginx_plus	r36
f5	nginx_plus	r36
f5	nginx_plus	r36
f5	waf	*
f5	waf	*
f5	waf	*
redhat	discovery	-
redhat	hardened_images	-
redhat	update_infrastructure	*
redhat	enterprise_linux	8.0
redhat	enterprise_linux	9.0
redhat	enterprise_linux	10.0

JSON

To clipboard

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CVE-2026-42055 (GCVE-0-2026-42055)

Vulnerability from cvelistv5 – Published: 2026-06-17 14:04 – Updated: 2026-07-28 12:04 X_F5

Title

NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability

Summary

Severity

8.1 (High)


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

9.2 (Critical)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-17 00:00 UTC

CWE

CWE-122 - Heap-based Buffer Overflow
CWE-131 - Incorrect Calculation of Buffer Size

Assigner

References

12 references

URL	Tags
https://my.f5.com/manage/s/article/K000161584	vendor-advisory
https://access.redhat.com/security/cve/CVE-2026-42055	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2489866	issue-trackingx_refsource_REDHAT
https://security.access.redhat.com/data/csaf/v2/v…	x_sadp-csaf-vex
https://access.redhat.com/errata/RHSA-2026:36364	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:38847	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36618	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36331	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:36639	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:46836	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:27197	vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:44481	vendor-advisoryx_refsource_REDHAT

Impacted products

13 products

Vendor	Product	Version
F5	NGINX Open Source	Affected: 1.13.10 , < 1.31.2 (custom) Affected: 1.30.2 , < 1.30.3 (custom)
F5	NGINX Plus	Affected: 37.0 , < 37.0.2.1 (custom) Affected: R36 , < R36 P6 (custom)
Red Hat	Red Hat Enterprise Linux 10	Unaffected: 2:1.26.3-6.el10_2.5 , < * (rpm) cpe:/o:redhat:enterprise_linux:10.2
Red Hat	Red Hat Enterprise Linux 8	Unaffected: 8100020260707171317.489197e6 , < * (rpm) cpe:/a:redhat:enterprise_linux:8
Red Hat	Red Hat Enterprise Linux 9	Unaffected: 2:1.20.1-28.el9_8.4 , < * (rpm) cpe:/a:redhat:enterprise_linux:9
Red Hat	Red Hat Enterprise Linux 9	Unaffected: 9080020260707164406.9 , < * (rpm) cpe:/a:redhat:enterprise_linux:9
Red Hat	Red Hat Enterprise Linux 9	Unaffected: 9080020260707110000.9 , < * (rpm) cpe:/a:redhat:enterprise_linux:9
Red Hat	Red Hat Discovery 2	Unaffected: 1784821750 , < * (rpm) cpe:/a:redhat:discovery:2::el9
Red Hat	Red Hat Hardened Images	Unaffected: 1.30.3-2.hum1 , < * (rpm) cpe:/a:redhat:hummingbird:1
Red Hat	Red Hat Update Infrastructure 5	Unaffected: 1784794818 , < * (rpm) cpe:/a:redhat:rhui:5::el9
Red Hat	Red Hat Update Infrastructure 5	Unaffected: 1784794778 , < * (rpm) cpe:/a:redhat:rhui:5::el9
Red Hat	Red Hat Update Infrastructure 5	Unaffected: 1784795076 , < * (rpm) cpe:/a:redhat:rhui:5::el9
Red Hat	Red Hat Openshift Data Foundation 4	cpe:/a:redhat:openshift_data_foundation:4

Date Public

2026-06-17 14:00

Credits

"F5 acknowledges Mufeed VH of Winfunc Research, Trung Nguyen (@everping) of CyStack, Feng Xue and XGPT of ThreatBook, Hcamael and 章鱼哥 of aipyapp, and Zhen Yan (AntAISecurityLab) 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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      "affected": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "ngx_http_proxy_v2_module",
            "ngx_http_grpc_module"
          ],
          "product": "NGINX Open Source",
          "vendor": "F5",
          "versions": [
            {
              "lessThan": "1.31.2",
              "status": "affected",
              "version": "1.13.10",
              "versionType": "custom"
            },
            {
              "lessThan": "1.30.3",
              "status": "affected",
              "version": "1.30.2",
              "versionType": "custom"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "modules": [
            "ngx_http_proxy_v2_module",
            "ngx_http_grpc_module"
          ],
          "product": "NGINX Plus",
          "vendor": "F5",
          "versions": [
            {
              "lessThan": "37.0.2.1",
              "status": "affected",
              "version": "37.0",
              "versionType": "custom"
            },
            {
              "lessThan": "R36 P6",
              "status": "affected",
              "version": "R36",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "\"F5 acknowledges Mufeed VH of Winfunc Research, Trung Nguyen (@everping) of CyStack, Feng Xue and XGPT of ThreatBook, Hcamael and \u7ae0\u9c7c\u54e5 of aipyapp, and Zhen Yan (AntAISecurityLab) for bringing this issue to our attention and following the highest standards of coordinated disclosure.\""
        }
      ],
      "datePublic": "2026-06-17T14:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cspan style=\"background-color: rgb(255, 255, 255);\"\u003eNGINX Plus and NGINX Open Source have a vulnerability in the \u003c/span\u003e\u003cstrong\u003engx_http_proxy_v2_module\u003c/strong\u003e\u003cspan style=\"background-color: rgb(255, 255, 255);\"\u003e\u0026nbsp;and \u003c/span\u003e\u003cstrong\u003engx_http_grpc_module\u003c/strong\u003e\u003cspan style=\"background-color: rgb(255, 255, 255);\"\u003e\u0026nbsp;modules. This vulnerability exists when the \u003c/span\u003e\u003cstrong\u003eproxy_http_version to 2\u003c/strong\u003e\u003cspan style=\"background-color: rgb(255, 255, 255);\"\u003e\u0026nbsp;or \u003c/span\u003e\u003cstrong\u003egrpc_pass\u003c/strong\u003e\u003cspan style=\"background-color: rgb(255, 255, 255);\"\u003e\u0026nbsp;directives are used to proxy HTTP/2 traffic, the \u003c/span\u003e\u003cstrong\u003eignore_invalid_headers\u003c/strong\u003e\u003cspan style=\"background-color: rgb(255, 255, 255);\"\u003e\u0026nbsp;directive is set to off, and the \u003c/span\u003e\u003cstrong\u003elarge_client_header_buffers\u003c/strong\u003e\u003cspan style=\"background-color: rgb(255, 255, 255);\"\u003e\u0026nbsp;directive size is larger than 2 megabytes. A remote, unauthenticated attacker, along with conditions beyond their control, could send large headers while creating an upstream request. This may cause a heap-based buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.\u003c/span\u003e \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated."
            }
          ],
          "value": "NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module\u00a0and ngx_http_grpc_module\u00a0modules. This vulnerability exists when the proxy_http_version to 2\u00a0or grpc_pass\u00a0directives are used to proxy HTTP/2 traffic, the ignore_invalid_headers\u00a0directive is set to off, and the large_client_header_buffers\u00a0directive size is larger than 2 megabytes. A remote, unauthenticated attacker, along with conditions beyond their control, could send large headers while creating an upstream request. This may cause a heap-based buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. \n\n\nNote: Software versions which have reached End of Technical Support (EoTS) are not evaluated."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        },
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 9.2,
            "baseSeverity": "CRITICAL",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "HIGH",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-122",
              "description": "CWE-122 Heap-based Buffer Overflow",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-17T14:04:32.520Z",
        "orgId": "9dacffd4-cb11-413f-8451-fbbfd4ddc0ab",
        "shortName": "f5"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://my.f5.com/manage/s/article/K000161584"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "tags": [
        "x_F5"
      ],
      "title": "NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability",
      "x_generator": {
        "engine": "F5 SIRTBot v1.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9dacffd4-cb11-413f-8451-fbbfd4ddc0ab",
    "assignerShortName": "f5",
    "cveId": "CVE-2026-42055",
    "datePublished": "2026-06-17T14:04:32.520Z",
    "dateReserved": "2026-06-02T21:45:04.818Z",
    "dateUpdated": "2026-07-28T12:04:38.243Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

FKIE_CVE-2026-42055

CVE-2026-42055 (GCVE-0-2026-42055)

Tags

Sightings

Nomenclature