Cyber Resilience

CVE-2026-85597

Access Control in Traefik ≤ 2.11.55

Public PoCAccess Control
Published
04 September 2026
Modified
08 October 2026
Patch / advisory
CVSS Score v4 8.2
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0035 27th percentile
Risk Priority 43 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-85597 is a high-severity Incorrect Authorization (CWE-863) vulnerability in Traefik Traefik. Its CVSS base score is 8.2 (High).

Operationally, ranked at the 27th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Traefik before v2.11.55 and v3.0.0 through v3.7.10 contain a TLS option conflict resolution vulnerability that allows unauthenticated attackers to bypass client-certificate authentication by creating conflicting TLS options on multi-host routers. Attackers can reach protected backends by exploiting shared TLS resolution…

more

across multiple hostnames in a single router rule, causing the strict mTLS requirement to fall back to default options for all hosts.

CWE(s)

Related Threats

CVEs Like This One

CVE-2026-65601Same product: Traefik Traefik
CVE-2026-65602Same product: Traefik Traefik
CVE-2026-54761Same product: Traefik Traefik
CVE-2026-41174Same product: Traefik Traefik
CVE-2026-88007Same product: Traefik Traefik
CVE-2026-88008Same product: Traefik Traefik
CVE-2026-54765Same product: Traefik Traefik
CVE-2024-52003Same product: Traefik Traefik
CVE-2026-48491Same product: Traefik Traefik
CVE-2026-54763Same product: Traefik Traefik

Affected Assets

traefik
traefik
≤ 2.11.55 · 3.0.0 — 3.7.11

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

AC-3 directly requires correct enforcement of authorization decisions on every access request, structurally preventing incorrect checks.

AC-24 ensures access-control decisions are made and applied consistently, reducing the chance of an incorrect authorization result.

A reference monitor that is always invoked and tamper-proof forces every authorization decision through a verified, correct path.

Least-privilege assignments shrink the set of authorizations that must be checked correctly, limiting exposure to flawed checks.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

blocks

Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.

blocks

A.5.18's provisioning, revocation, review and adjustment of access rights (incl. before role changes/termination, with segregation and owner approval) directly stops incorrect authorization decisions from being exploitable in the vast majority of cases; the bounded remainder is incorrectness inside the authorization logic itself (e.g. flawed conditional or missing check) rather than rights that were wrongly granted.

blocks

A.8.3 directly mandates restricting access to information per policies via configuration, identity/group controls, isolation, and dynamic techniques that enforce correct authorization decisions, addressing most but not all slices of CWE-863 (e.g., remainder in non-access-decision authorization errors like timing or environmental factors).

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-863, a class-level weakness, and none of its children carries one either.

References