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CVE-2026-48020

Traefik authentication bypass

10.0 CRITICALPublic exploitEPSS 0.78%
  1. Published23 Jun 2026

Description

Traefik is an HTTP reverse proxy and load balancer. Prior to 2.11.48, 3.6.19, and 3.7.3, there is a high severity vulnerability in Traefik's StripPrefix middleware that allows an unauthenticated attacker to bypass route-level authentication and authorization. When a public router matches on a PathPrefix rule and applies the StripPrefix middleware, a request path containing .. or its percent-encoded form %2e%2e can match the public route at routing time and then, after the prefix is stripped and the path is normalized, resolve to a path served by a separate, authenticated router. As a result, an attacker can reach protected backend paths — such as admin or internal configuration endpoints — without satisfying the authentication middleware attached to the protected router. This vulnerability is fixed in 2.11.48, 3.6.19, and 3.7.3.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

Affected products

Traefik≥ 3.0.0 < 3.6.19 · ≥ 3.7.0 < 3.7.3 · < 2.11.48

Remediation

Fixed in
Traefik≥ 3.6.19

References

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Frequently asked

Is CVE-2026-48020 being actively exploited?

CVE-2026-48020 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.78%.

How severe is CVE-2026-48020?

CVE-2026-48020 has a CVSS 3.1 base score of 10.0, rated critical. EPSS estimates a 0.78% probability of exploitation.

Which products are affected by CVE-2026-48020?

Affected products include Traefik.

How do I fix CVE-2026-48020?

Upgrade affected software to a fixed version, for example Traefik 3.6.19 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-48020 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.