When multiple server blocks are configured to share the same IP address and port, an attacker can use session resumption to bypass client certificate authentication requirements on these servers. This vulnerability arises when TLS Session Tickets https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key are used and/or the SSL session cache https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache are used in the default server and the default server is performing client certificate authentication. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

nginx nginx-CVE-2025-23419.html: SSL session reuse vulnerability

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

  - When multiple server blocks are configured to share the same IP address and port, an attacker can use     session resumption to bypass client certificate authentication requirements on these servers. This     vulnerability arises when TLS Session Tickets     https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key are used and/or the SSL     session cache https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache are used in the     default server and the default server is performing client certificate authentication. Note: Software     versions which have reached End of Technical Support (EoTS) are not evaluated. (CVE-2025-23419)

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

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2025-842 advisory.

    When multiple server blocks are configured to share the same IP address and port, an attacker can use     session resumption to bypass client certificate authentication requirements on these servers. This     vulnerability arises when  TLS Session Tickets     https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key  are used and/or the  SSL     session cache https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache  are used in the     default server and the default server is performing client certificate authentication.

    Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
    (CVE-2025-23419)

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

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

The remote Ubuntu 20.04 LTS / 22.04 LTS / 24.10 host has packages installed that are affected by a vulnerability as referenced in the USN-7285-1 advisory.

    It was discovered that nginx incorrectly handled when multiple server blocks are configured to share the     same IP address and port. An attacker could use this issue to use session resumption to bypass client     certificate authentication requirements on these servers. This issue only affected Ubuntu 24.10.

    A buffer overflow and a null pointer deref was fixed in nginx rtmp module (#LP 1977718). This issue only     affected Ubuntu 20.04 LTS and Ubuntu 22.04 LTS.

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

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

The version of nginx installed on the remote Azure Linux 3.0 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the CVE-2025-23419 advisory.

  - When multiple server blocks are configured to share the same IP address and port, an attacker can use     session resumption to bypass client certificate authentication requirements on these servers. This     vulnerability arises when TLS Session Tickets     https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key are used and/or the SSL     session cache https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache are used in the     default server and the default server is performing client certificate authentication. Note: Software     versions which have reached End of Technical Support (EoTS) are not evaluated. (CVE-2025-23419)

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

The version of nginx installed on the remote CBL Mariner 2.0 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the CVE-2025-23419 advisory.

  - When multiple server blocks are configured to share the same IP address and port, an attacker can use     session resumption to bypass client certificate authentication requirements on these servers. This     vulnerability arises when TLS Session Tickets     https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_ticket_key are used and/or the SSL     session cache https://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_session_cache are used in the     default server and the default server is performing client certificate authentication. Note: Software     versions which have reached End of Technical Support (EoTS) are not evaluated. (CVE-2025-23419)

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

The remote Fedora 40 host has packages installed that are affected by a vulnerability as referenced in the FEDORA-2025-016ed44ddc advisory.


    Changes with nginx 1.26.3                                        05 Feb 2025

        *) Security: insufficient check in virtual servers handling with TLSv1.3            SNI allowed to reuse SSL sessions in a different virtual server, to            bypass client SSL certificates verification (CVE-2025-23419).

        *) Bugfix: in the ngx_http_mp4_module.
           Thanks to Nils Bars.

        *) Workaround: gzip filter failed to use preallocated memory alerts            appeared in logs when using zlib-ng.

        *) Bugfix: nginx could not build libatomic library using the library            sources if the --with-libatomic=DIR option was used.

        *) Bugfix: nginx now ignores QUIC version negotiation packets from            clients.

        *) Bugfix: nginx could not be built on Solaris 10 and earlier with the            ngx_http_v3_module.

        *) Bugfixes in HTTP/3.

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

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

The remote Fedora 41 host has packages installed that are affected by a vulnerability as referenced in the FEDORA-2025-66ebd291f8 advisory.


    Changes with nginx 1.26.3                                        05 Feb 2025

        *) Security: insufficient check in virtual servers handling with TLSv1.3            SNI allowed to reuse SSL sessions in a different virtual server, to            bypass client SSL certificates verification (CVE-2025-23419).

        *) Bugfix: in the ngx_http_mp4_module.
           Thanks to Nils Bars.

        *) Workaround: gzip filter failed to use preallocated memory alerts            appeared in logs when using zlib-ng.

        *) Bugfix: nginx could not build libatomic library using the library            sources if the --with-libatomic=DIR option was used.

        *) Bugfix: nginx now ignores QUIC version negotiation packets from            clients.

        *) Bugfix: nginx could not be built on Solaris 10 and earlier with the            ngx_http_v3_module.

        *) Bugfixes in HTTP/3.

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

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

According to its Server response header, the installed version of nginx is from 1.11.4 to 1.26.2 or 1.27.x prior to 1.27.4. It is, therefore, affected by a SSL session reuse vulnerability due to insufficient check in virtual servers handling with TLSv1.3 SNI allowed to reuse SSL sessions in a different virtual server, to bypass client SSL certificates verification.

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

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the 9761af78-e3e4-11ef-9f4a-589cfc10a551 advisory.

    The nginx development team reports:
    This update fixes the SSL session reuse vulnerability.

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

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
230539	Linux Distros Unpatched Vulnerability : CVE-2025-23419	Nessus	Misc.	medium
216803	Amazon Linux 2023 : nginx, nginx-all-modules, nginx-core (ALAS2023-2025-842)	Nessus	Amazon Linux Local Security Checks	medium
216699	Ubuntu 20.04 LTS / 22.04 LTS / 24.10 : nginx vulnerability (USN-7285-1)	Nessus	Ubuntu Local Security Checks	medium
216568	Azure Linux 3.0 Security Update: nginx (CVE-2025-23419)	Nessus	Azure Linux Local Security Checks	medium
216360	CBL Mariner 2.0 Security Update: nginx (CVE-2025-23419)	Nessus	MarinerOS Local Security Checks	medium
216348	Fedora 40 : nginx / nginx-mod-fancyindex / nginx-mod-modsecurity / etc (2025-016ed44ddc)	Nessus	Fedora Local Security Checks	medium
216345	Fedora 41 : nginx / nginx-mod-fancyindex / nginx-mod-modsecurity / etc (2025-66ebd291f8)	Nessus	Fedora Local Security Checks	medium
114595	Nginx 1.11.4 < 1.26.3 SSL Session Reuse	Web App Scanning	Component Vulnerability	medium
114594	Nginx 1.27.x < 1.27.4 SSL Session Reuse	Web App Scanning	Component Vulnerability	medium
215045	FreeBSD : nginx-devel -- SSL session reuse vulnerability (9761af78-e3e4-11ef-9f4a-589cfc10a551)	Nessus	FreeBSD Local Security Checks	medium

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