Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC AT PR UI VC VI VA CVSS EPSS %ile KEV N L N N N N N N 7.8 .0028 20.5 —
AFFECTED Product Versions Fixed traefik >= 3.7.0, < 3.7.3 – —
TIMELINE May 21 Reserved by GitHub_M Jun 23 EXPLOIT PUBLISHED — CVE-2026-48491 (traefik). Public exploit reference added. Jun 23 Published (CNA: GitHub_M)
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.
| Date | Event | Detail |
|---|---|---|
| May 21, 2026 | Reserved | Reserved by GitHub_M |
| June 23, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-48491 (traefik). Public exploit reference added. |
| June 23, 2026 | Published | Published (CNA: GitHub_M) |
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|---|---|---|---|
| traefik | traefik | — | >= 3.7.0, < 3.7.3 | — |
Authoritative record: CVE-2026-48491 at cve.org
Vendors: traefik
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-48491 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.