It was discovered that the nginx ngx_mail_smtp_module module incorrectly handled certain memory operations when doing SMTP authentication. This could possibly result in sensitive information being sent to the authentication server. ( CVE-2025-53859 ) It was discovered that nginx incorrectly handled proxying to upstream TLS servers. An attacker could possibly use this issue to insert plain text data into the response from an upstream proxied server. ( CVE-2026-1642 ) It was discovered that the nginx ngx_mail_auth_http_module module incorrectly handled certain requests. An attacker could possibly use this issue to cause nginx to crash, resulting in a denial of service. ( CVE-2026-27651 ) It was discovered that the nginx ngx_http_dav_module module incorrectly handled certain destination URIs. An attacker could use...
It was discovered that the nginx ngx_mail_smtp_module module incorrectly handled certain memory operations when doing SMTP authentication. This could possibly result in sensitive information being sent to the authentication server. ( CVE-2025-53859 )
It was discovered that nginx incorrectly handled proxying to upstream TLS servers. An attacker could possibly use this issue to insert plain text data into the response from an upstream proxied server. ( CVE-2026-1642 )
It was discovered that the nginx ngx_mail_auth_http_module module incorrectly handled certain requests. An attacker could possibly use this issue to cause nginx to crash, resulting in a denial of service. ( CVE-2026-27651 )
It was discovered that the nginx ngx_http_dav_module module incorrectly handled certain destination URIs. An attacker could use...
It was discovered that the nginx ngx_mail_smtp_module module incorrectly handled certain memory operations when doing SMTP authentication. This could possibly result in sensitive information being sent to the authentication server. ( CVE-2025-53859 ) It was discovered that nginx incorrectly handled proxying to upstream TLS servers. An attacker could possibly use this issue to insert plain text data into the response from an upstream proxied server. ( CVE-2026-1642 ) It was discovered that the nginx ngx_mail_auth_http_module module incorrectly handled certain requests. An attacker could possibly use this issue to cause nginx to crash, resulting in a denial of service. ( CVE-2026-27651 ) It was discovered that the nginx ngx_http_dav_module module incorrectly handled certain destination URIs. An attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly modify source or destination names outside of the document root. ( CVE-2026-27654 ) It was discovered that the nginx ngx_http_mp4_module module incorrectly handled certain MP4 files. An attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly execute arbitrary code. ( CVE-2026-27784 , CVE-2026-32647 ) It was discovered that the nginx ngx_mail_smtp_module module incorrectly handled certain CRLF sequences. An attacker could possibly use this issue to inject arbitrary SMTP headers. ( CVE-2026-28753 ) It was discovered that nginx contained a use-after-free vulnerability in the ngx_http_ssl_module module when client certificate verification and OCSP validation were enabled. A remote attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly modify data in memory. ( CVE-2026-40701 ) It was discovered that nginx did not properly handle certain proxied responses in the ngx_http_charset_module module. A remote attacker could possibly use this issue to obtain sensitive information or cause nginx to crash, resulting in a denial of service. ( CVE-2026-42934 ) It was discovered that the nginx ngx_http_rewrite_module component incorrectly handled certain rewrite directives. A remote attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly execute arbitrary code. ( CVE-2026-42945 ) It was discovered that nginx did not properly process certain SCGI and uWSGI responses. An attacker able to perform a machine-in-the-middle attack could possibly use this issue to obtain sensitive information or cause nginx to crash, resulting in a denial of service. ( CVE-2026-42946 ) It was discovered that nginx incorrectly handled certain rewrite rules in the ngx_http_rewrite_module module. A remote attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly execute arbitrary code. ( CVE-2026-9256 )
It was discovered that the nginx ngx_mail_smtp_module module incorrectly handled certain memory operations when doing SMTP authentication. This could possibly result in sensitive information being sent to the authentication server. ( CVE-2025-53859 )
It was discovered that nginx incorrectly handled proxying to upstream TLS servers. An attacker could possibly use this issue to insert plain text data into the response from an upstream proxied server. ( CVE-2026-1642 )
It was discovered that the nginx ngx_mail_auth_http_module module incorrectly handled certain requests. An attacker could possibly use this issue to cause nginx to crash, resulting in a denial of service. ( CVE-2026-27651 )
It was discovered that the nginx ngx_http_dav_module module incorrectly handled certain destination URIs. An attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly modify source or destination names outside of the document root. ( CVE-2026-27654 )
It was discovered that the nginx ngx_http_mp4_module module incorrectly handled certain MP4 files. An attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly execute arbitrary code. ( CVE-2026-27784 , CVE-2026-32647 )
It was discovered that the nginx ngx_mail_smtp_module module incorrectly handled certain CRLF sequences. An attacker could possibly use this issue to inject arbitrary SMTP headers. ( CVE-2026-28753 )
It was discovered that nginx contained a use-after-free vulnerability in the ngx_http_ssl_module module when client certificate verification and OCSP validation were enabled. A remote attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly modify data in memory. ( CVE-2026-40701 )
It was discovered that nginx did not properly handle certain proxied responses in the ngx_http_charset_module module. A remote attacker could possibly use this issue to obtain sensitive information or cause nginx to crash, resulting in a denial of service. ( CVE-2026-42934 )
It was discovered that the nginx ngx_http_rewrite_module component incorrectly handled certain rewrite directives. A remote attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly execute arbitrary code. ( CVE-2026-42945 )
It was discovered that nginx did not properly process certain SCGI and uWSGI responses. An attacker able to perform a machine-in-the-middle attack could possibly use this issue to obtain sensitive information or cause nginx to crash, resulting in a denial of service. ( CVE-2026-42946 )
It was discovered that nginx incorrectly handled certain rewrite rules in the ngx_http_rewrite_module module. A remote attacker could use this issue to cause nginx to crash, resulting in a denial of service, or possibly execute arbitrary code. ( CVE-2026-9256 )
In general, a standard system update will make all the necessary changes.
The problem can be corrected by updating your system to the following package versions:
Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.
The full story
This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.
