CVE-2026-48491

CRITICALNVD 10.010.0—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 10.0 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 80% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
10.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 10.0Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
10.0
EG Score
10.0(medium)
EG Risk
60(Track)
EG Risk 60/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity100% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
20%
KEV
Not listed

Published

June 16, 2026

Last Modified

July 15, 2026

Advisory Details (5)

Auto-updated Jul 22, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github, redhat.
redhat
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48491.json
redhat

2491923 – (CVE-2026-48491) CVE-2026-48491 Traefik: Traefik: Unauthorized access due to mutual TLS bypass

https://bugzilla.redhat.com/show_bug.cgi?id=2491923
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-48491
github Patch Available🟡 PoC Available

SNICheck ignores wildcard TLSOptions mappings, allowing domain-fronted mTLS bypass · Advisory · traefik/traefik · GitHub

https://github.com/traefik/traefik/security/advisories/GHSA-5r4w-85f3-pw66
github_release Patch Available

v3.7.3

Patch available: traefik/traefik v3.7.3

https://github.com/traefik/traefik/releases/tag/v3.7.3

Vendor Advisories for CVE-2026-48491(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
Traefik—3.7.3—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 34× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-26 19:50 UTCEG score recompute
  2. 2026-07-26 14:54 UTCEPSS rescore
  3. 2026-07-25 14:18 UTCEPSS rescore
  4. 2026-07-24 14:18 UTCEPSS rescore
  5. 2026-07-23 14:18 UTCEPSS rescore
  6. 2026-07-23 03:18 UTCEG score recompute
  7. 2026-07-22 14:08 UTCEPSS rescore
  8. 2026-07-21 15:25 UTCEPSS rescore
  9. 2026-07-20 17:08 UTCEPSS rescore
  10. 2026-07-19 14:31 UTCEPSS rescore
  11. 2026-07-19 02:29 UTCEPSS rescore
  12. 2026-07-18 10:04 UTCEPSS rescore
  13. 2026-07-16 17:03 UTCEPSS rescore
  14. 2026-07-15 16:57 UTCEPSS rescore
  15. 2026-07-15 02:26 UTCNVD updateCVSS v3 → 10
  16. 2026-07-15 02:00 UTCEPSS rescore
  17. 2026-07-15 01:21 UTCMITRE cvelistV5CVSS v3 → 9.1
  18. 2026-07-13 22:30 UTCEPSS rescore
  19. 2026-07-13 06:13 UTCEPSS rescore
  20. 2026-07-12 05:46 UTCEPSS rescore
  21. 2026-07-11 08:27 UTCEPSS rescore
  22. 2026-07-09 19:10 UTCEPSS rescore
  23. 2026-07-08 15:16 UTCEPSS rescore
  24. 2026-07-07 13:46 UTCEPSS rescore
  25. 2026-07-06 16:27 UTCEPSS rescore
Show 17 more
  1. 2026-07-06 02:23 UTCEPSS rescore
  2. 2026-07-05 02:30 UTCEPSS rescore
  3. 2026-07-01 15:07 UTCEPSS rescore
  4. 2026-06-30 23:22 UTCEPSS rescore
  5. 2026-06-29 14:06 UTCEPSS rescore
  6. 2026-06-29 14:06 UTCEPSS rescore
  7. 2026-06-28 14:07 UTCEPSS rescore
  8. 2026-06-28 04:56 UTCEPSS rescore
  9. 2026-06-28 04:56 UTCEPSS rescore
  10. 2026-06-27 03:08 UTCEPSS rescore
  11. 2026-06-27 00:34 UTCEG score recompute▲ 2.20
  12. 2026-06-26 17:41 UTCNVD updateCVSS v3 → 10 · severity → CRITICAL
  13. 2026-06-25 13:49 UTCEPSS rescore
  14. 2026-06-24 14:05 UTCEPSS rescore
  15. 2026-06-24 12:03 UTCEG score recompute▲ 7.80
  16. 2026-06-24 12:01 UTCNVD updateCVSS v3 → 7.8 · CVSS v4 → 7.8
  17. 2026-06-16 19:06 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-48491?
CVE-2026-48491 is a critical vulnerability published on June 16, 2026. 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…
When was CVE-2026-48491 disclosed?
CVE-2026-48491 was first published in the National Vulnerability Database on June 16, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-48491 actively exploited?
CVE-2026-48491 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 79.8% of all scored CVEs.
What is the CVSS score of CVE-2026-48491?
CVE-2026-48491 has a CVSS v3 base score of 10.0 (NVD).
How do I remediate CVE-2026-48491?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-48491, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-48491

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