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

Vulnerability from cvelistv5 – Published: 2026-06-17 14:04 – Updated: 2026-06-30 03:20 X_F5
VLAI
Title
NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability
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.
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 (v2.0.3)
CWE
  • CWE-122 - Heap-based Buffer Overflow
  • CWE-131 - Incorrect Calculation of Buffer Size
Assigner
f5
References
Impacted products
Vendor Product Version
F5 NGINX Open Source Affected: 1.13.10 , < 1.31.2 (custom)
Affected: 1.30.2 , < 1.30.3 (custom)
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F5 NGINX Plus Affected: 37.0 , < 37.0.2.1 (custom)
Affected: R36 , < R36 P6 (custom)
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Red Hat Red Hat Hardened Images     cpe:/a:redhat:hummingbird:1
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Red Hat Red Hat Enterprise Linux 10     cpe:/o:redhat:enterprise_linux:10
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Red Hat Red Hat Enterprise Linux 8     cpe:/o:redhat:enterprise_linux:8
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Red Hat Red Hat Enterprise Linux 9     cpe:/o:redhat:enterprise_linux:9
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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."
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      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-42055\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-06-17T15:43:07.643763Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-06-17T15:43:12.416Z\"}}], \"cna\": {\"tags\": [\"x_F5\"], \"title\": \"NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability\", \"source\": {\"discovery\": \"EXTERNAL\"}, \"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.\\\"\"}], \"metrics\": [{\"format\": \"CVSS\", \"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 8.1, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}, {\"format\": \"CVSS\", \"cvssV4_0\": {\"Safety\": \"NOT_DEFINED\", \"version\": \"4.0\", \"Recovery\": \"NOT_DEFINED\", \"baseScore\": 9.2, \"Automatable\": \"NOT_DEFINED\", \"attackVector\": \"NETWORK\", \"baseSeverity\": \"CRITICAL\", \"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\", \"providerUrgency\": \"NOT_DEFINED\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"HIGH\", \"attackRequirements\": \"PRESENT\", \"privilegesRequired\": \"NONE\", \"subIntegrityImpact\": \"NONE\", \"vulnIntegrityImpact\": \"HIGH\", \"subAvailabilityImpact\": \"NONE\", \"vulnAvailabilityImpact\": \"HIGH\", \"subConfidentialityImpact\": \"NONE\", \"vulnConfidentialityImpact\": \"HIGH\", \"vulnerabilityResponseEffort\": \"NOT_DEFINED\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"GENERAL\"}]}], \"affected\": [{\"vendor\": \"F5\", \"modules\": [\"ngx_http_proxy_v2_module\", \"ngx_http_grpc_module\"], \"product\": \"NGINX Open Source\", \"versions\": [{\"status\": \"affected\", \"version\": \"1.13.10\", \"lessThan\": \"1.31.2\", \"versionType\": \"custom\"}, {\"status\": \"affected\", \"version\": \"1.30.2\", \"lessThan\": \"1.30.3\", \"versionType\": \"custom\"}], \"defaultStatus\": \"unknown\"}, {\"vendor\": \"F5\", \"modules\": [\"ngx_http_proxy_v2_module\", \"ngx_http_grpc_module\"], \"product\": \"NGINX Plus\", \"versions\": [{\"status\": \"affected\", \"version\": \"37.0\", \"lessThan\": \"37.0.2.1\", \"versionType\": \"custom\"}, {\"status\": \"affected\", \"version\": \"R36\", \"lessThan\": \"R36 P6\", \"versionType\": \"custom\"}], \"defaultStatus\": \"unaffected\"}], \"datePublic\": \"2026-06-17T14:00:00.000Z\", \"references\": [{\"url\": \"https://my.f5.com/manage/s/article/K000161584\", \"tags\": [\"vendor-advisory\"]}], \"x_generator\": {\"engine\": \"F5 SIRTBot v1.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module\\u00a0and ngx_http_grpc_module\\u00a0modules. 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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.\", \"base64\": false}]}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-122\", \"description\": \"CWE-122 Heap-based Buffer Overflow\"}]}], \"providerMetadata\": {\"orgId\": \"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab\", \"shortName\": \"f5\", \"dateUpdated\": \"2026-06-17T14:04:32.520Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-42055\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-06-18T03:57:46.697Z\", \"dateReserved\": \"2026-06-02T21:45:04.818Z\", \"assignerOrgId\": \"9dacffd4-cb11-413f-8451-fbbfd4ddc0ab\", \"datePublished\": \"2026-06-17T14:04:32.520Z\", \"assignerShortName\": \"f5\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


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Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.