How severe is CVE-2026-85594?

CVE-2026-85594 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-85594 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-85594?

CVE-2026-85594 affects Traefik. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-85594?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-85594 published?

CVE-2026-85594 was published on 2026-09-04 and last updated on 2026-09-16.

CVE-2026-85594

CVE-2026-85594 is a critical-severity vulnerability in Traefik with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-639.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 7.0
EPSS exploit prediction: 0% (39th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-639
Affected product: Traefik
Published: 2026-09-04
Last modified: 2026-09-16

Description

Traefik versions from v3.7.1 fail to enforce crossProviderNamespaces restrictions on the traefik.ingress.kubernetes.io/service.middlewares Service annotation in the Kubernetes Ingress provider. A namespace-limited tenant excluded from the allowlist can attach an operator-owned middleware to its Service, and if that middleware injects backend credentials, recover them at a controlled backend.

Frequently asked questions

What is CVE-2026-85594?: Traefik versions from v3.7.1 fail to enforce crossProviderNamespaces restrictions on the traefik.ingress.kubernetes.io/service.middlewares Service annotation in the Kubernetes Ingress provider. A namespace-limited tenant excluded from the allowlist can attach an operator-owned middleware to its Service, and if that middleware injects backend credentials, recover them at a controlled backend.
How severe is CVE-2026-85594?: CVE-2026-85594 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-85594 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-85594?: CVE-2026-85594 affects Traefik. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-85594?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-85594 published?: CVE-2026-85594 was published on 2026-09-04 and last updated on 2026-09-16.

References

Affected products (1)

cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*

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