Traefik is an HTTP reverse proxy and load balancer. From 3.7.0 until 3.7.3, there is a high severity vulnerability in Traefik's domain-fronting protection (SNICheck) that allows an unauthenticated client to bypass mutual TLS enforced through wildcard router TLSOptions. When a router uses a wildcard host rule such as Host(*.example.com) with stricter TLS options (for example RequireAndVerifyClientCert), SNICheck resolves the TLS options for the HTTP Host header using exact map lookups only and never applies wildcard matching. If another permissive SNI is served on the same entrypoint, an attacker can complete the TLS handshake under the permissive options and then send an HTTP Host header targeting the wildcard-protected backend, reaching it without presenting a client certificate. This affects the regular HTTPS / HTTP-2 path and does not require HTTP/3. This vulnerability is fixed in 3.7.3.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - Traefik is an HTTP reverse proxy and load balancer. From 3.7.0 until 3.7.3, there is a high severity
    vulnerability in Traefik's domain-fronting protection (SNICheck) that allows an unauthenticated client to
    bypass mutual TLS enforced through wildcard router TLSOptions. When a router uses a wildcard host rule
    such as Host(*.example.com) with stricter TLS options (for example RequireAndVerifyClientCert), SNICheck
    resolves the TLS options for the HTTP Host header using exact map lookups only and never applies wildcard
    matching. If another permissive SNI is served on the same entrypoint, an attacker can complete the TLS
    handshake under the permissive options and then send an HTTP Host header targeting the wildcard-protected
    backend, reaching it without presenting a client certificate. This affects the regular HTTPS / HTTP-2 path
    and does not require HTTP/3. This vulnerability is fixed in 3.7.3. (CVE-2026-48491)

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 57e69b2c-67b2-11f1-b3b6-5404a68ad561 advisory.

    The traefik project releases a new version addressing multiple CVEs:

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.

ID	Name	Product	Family	Severity
443295	SCA: security update for Traefik (GHSA-5r4w-85f3-pw66)	Tenable Cloud Security	SCA Checks	high
443295	SCA: security update for Traefik (GHSA-5r4w-85f3-pw66)	Tenable Self-Hosted Container Security	SCA Checks	high
321074	FreeBSD : traefik -- Multiple vulnerabilities (57e69b2c-67b2-11f1-b3b6-5404a68ad561)	Nessus	FreeBSD Local Security Checks	high

Detections

Analytics

CVE-2026-48491

high

Tenable Plugins

high

high

high