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.

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the 46b654f8-6b28-11f1-b8e5-3497f65b111b advisory.

    The nginx developers report:

           A heap memory buffer overflow vulnerability when using the            ignore_invalid_headers off; and large_client_header_buffers            directives with large configured values while proxying a specially            crafted request to an HTTP/2 or gRPC backend may allow memory            corruption or a segmentation fault in a worker process            (CVE-2026-42055).


           A heap memory buffer overread vulnerability while handling a            specially crafted response with decoding from UTF-8 via the            charset_map directive may allow limited disclosure of worker            process memory or a segmentation fault in a worker process            (CVE-2026-48142).


Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2026-42055)

Note that Nessus relies on the presence of the package as reported by the vendor.

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the 08b0c0f6-6a85-11f1-b8e5-3497f65b111b advisory.

    The nginx developers report:

           A use-after-free vulnerability when using HTTP/3 and processing a            specially crafted QUIC session may allow memory corruption or a            segmentation fault in a worker process (CVE-2026-42530).


           A heap memory buffer overflow vulnerability when using the            ignore_invalid_headers off; and large_client_header_buffers            directives with large configured values while proxying a specially            crafted request to an HTTP/2 or gRPC backend may allow memory            corruption or a segmentation fault in a worker process            (CVE-2026-42055).


           A heap memory buffer overread vulnerability while handling a            specially crafted response with decoding from UTF-8 via the            charset_map directive may allow limited disclosure of worker            process memory or a segmentation fault in a worker process            (CVE-2026-48142).


Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Fedora 45 host has packages installed that are affected by multiple vulnerabilities as referenced in the FEDORA-2026-e212182e6e advisory.

    nginx-mod-brotli:

    - Rebuild for 1.30.3

    nginx-mod-fancyindex:

    - Rebuild for 1.30.3

    nginx-mod-modsecurity:

    - Rebuild for 1.30.3

    nginx-mod-headers-more:

    - Rebuild for 1.30.3

    nginx-mod-naxsi:

    - Rebuild for 1.30.3

    nginx-mod-js-challenge:

    - Rebuild for 1.30.3

    nginx-mod-vts:

    - Rebuild for 1.30.3

    nginx:

    - update to 1.30.3
    - fixes CVE-2026-42055, CVE-2026-42530 and CVE-2026-48142



Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The installed version of nginx is 1.13.10 prior to 1.30.3, or 1.31.x prior to 1.31.2. It is, therefore, affected by the following issue :

  - 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. (CVE-2026-42055)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
321768	FreeBSD : nginx -- multiple vulnerabilities (46b654f8-6b28-11f1-b8e5-3497f65b111b)	Nessus	FreeBSD Local Security Checks	critical
321739	Linux Distros Unpatched Vulnerability : CVE-2026-42055	Nessus	Misc.	critical
321716	FreeBSD : nginx -- multiple vulnerabilities (08b0c0f6-6a85-11f1-b8e5-3497f65b111b)	Nessus	FreeBSD Local Security Checks	critical
321546	Fedora 45 : nginx / nginx-mod-brotli / nginx-mod-fancyindex / etc (2026-e212182e6e)	Nessus	Fedora Local Security Checks	critical
321534	nginx 1.13.10 < 1.30.3 / 1.31.x < 1.31.2 Buffer Overflow	Nessus	Web Servers	critical

Detections

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CVE-2026-42055

critical

Tenable Plugins

critical

critical

critical

critical

critical